Add custom post type to BeTheme by Muffin Group

functions.php

//add this to your functions.php or include it there from another file.

function mytheme_includes() {
	
    if (! class_exists('Mfn_Post_Type_Video')) { //change references to 'Video or video' to your post type
        class Mfn_Post_Type_Video extends Mfn_Post_Type
        {

            /**
             * Mfn_Post_Type_Video constructor
             */

            public function __construct()
            {
                parent::__construct();

                // fires after WordPress has finished loading but before any headers are sent
                add_action('init', array($this, 'register'));

                // admin only methods

                if( is_admin() ){
                    $this->fields = $this->set_fields();
                    $this->builder = new Mfn_Builder_Admin();
                }

            }

            /**
             * Set post type fields
             */

            private function set_fields(){

                return array(
            'id' => 'mfn-meta-video',
            'title' => esc_html__('Video Options', 'mfn-opts'),
            'page' => 'video',
            'context' => 'normal',
            'priority' => 'high',
            'fields' => array(

                // layout

                array(
                    'id' => 'mfn-meta-info-layout',
                    'type' => 'info',
                    'title' => '',
                    'desc' => __('Layout', 'mfn-opts'),
                    'class' => 'mfn-info',
                ),

                array(
                    'id' => 'mfn-post-hide-content',
                    'type' => 'switch',
                    'title' => __('Hide The Content', 'mfn-opts'),
                    'sub_desc' => __('Hide the content from the WordPress editor', 'mfn-opts'),
                    'desc' => __('<strong>Turn it ON if you build content using Content Builder</strong><br />Use the Content item if you want to display the Content from editor within the Content Builder', 'mfn-opts'),
                    'options' => array('1' => 'On', '0' => 'Off'),
                    'std' => '0'
                ),

                array(
                    'id' => 'mfn-post-layout',
                    'type' => 'radio_img',
                    'title' => __('Layout', 'mfn-opts'),
                    'desc' => __('<b>Full width</b> sections works only <b>without</b> sidebars', 'mfn-opts'),
                    'options' => array(
                        'no-sidebar' => array('title' => 'Full width. No sidebar', 'img' => MFN_OPTIONS_URI.'img/1col.png'),
                        'left-sidebar' => array('title' => 'Left Sidebar', 'img' => MFN_OPTIONS_URI.'img/2cl.png'),
                        'right-sidebar' => array('title' => 'Right Sidebar', 'img' => MFN_OPTIONS_URI.'img/2cr.png'),
                        'both-sidebars' => array('title' => 'Both Sidebars', 'img' => MFN_OPTIONS_URI.'img/2sb.png'),
                    ),
                    'std' => mfn_opts_get('sidebar-layout'),
                ),

                array(
                    'id' => 'mfn-post-sidebar',
                    'type' => 'select',
                    'title' => __('Sidebar', 'mfn-opts'),
                    'desc' => __('Shows only if layout with sidebar is selected', 'mfn-opts'),
                    'options' => mfn_opts_get('sidebars'),
                ),

                array(
                    'id' => 'mfn-post-sidebar2',
                    'type' => 'select',
                    'title' => __('Sidebar 2nd', 'mfn-opts'),
                    'desc' => __('Shows only if layout with both sidebars is selected', 'mfn-opts'),
                    'options' => mfn_opts_get('sidebars'),
                ),

                array(
                    'id' => 'mfn-post-template',
                    'type' => 'select',
                    'title' => __('Template', 'mfn-opts'),
                    'options' => array(
                        '' => __('Default Template', 'mfn-opts'),
                        'builder' => __('Builder', 'mfn-opts'),
                        'intro' => __('Intro Header', 'mfn-opts'),
                    ),
                ),

                // media

                array(
                    'id' => 'mfn-meta-info-media',
                    'type' => 'info',
                    'title' => '',
                    'desc' => __('Media', 'mfn-opts'),
                    'class' => 'mfn-info',
                ),

                array(
                    'id' => 'mfn-post-slider',
                    'type' => 'select',
                    'title' => __('Slider | Revolution Slider', 'mfn-opts'),
                    'desc' => __('Select one from the list of available <a target="_blank" href="admin.php?page=revslider">Revolution Sliders</a>', 'mfn-opts'),
                    'options' => Mfn_Builder_Helper::get_sliders('rev'),
                ),

                array(
                    'id' => 'mfn-post-slider-layer',
                    'type' => 'select',
                    'title' => __('Slider | Layer Slider', 'mfn-opts'),
                    'desc' => __('Select one from the list of available <a target="_blank" href="admin.php?page=layerslider">Layer Sliders</a>', 'mfn-opts'),
                    'options' => Mfn_Builder_Helper::get_sliders('layer'),
                ),

                array(
                    'id' => 'mfn-post-video',
                    'type' => 'text',
                    'title' => __('Video | ID', 'mfn-opts'),
                    'sub_desc' => __('YouTube or Vimeo', 'mfn-opts'),
                    'desc' => __('It`s placed in every YouTube & Vimeo video, for example:<br /><b>YouTube:</b> http://www.youtube.com/watch?v=<u>WoJhnRczeNg</u><br /><b>Vimeo:</b> http://vimeo.com/<u>62954028</u>', 'mfn-opts'),
                    'class' => 'small-text mfn-post-format video'
                ),

                array(
                    'id' => 'mfn-post-video-mp4',
                    'type' => 'upload',
                    'title' => __('Video | HTML5', 'mfn-opts'),
                    'sub_desc' => __('m4v [.mp4]', 'mfn-opts'),
                    'desc' => __('<strong>Notice:</strong> HTML5 video works only in modern browsers', 'mfn-opts'),
                    'class' => __('video', 'mfn-opts'),
                ),

                array(
                    'id' => 'mfn-post-header-bg',
                    'type' => 'upload',
                    'title' => __('Header Image', 'mfn-opts'),
                ),

                array(
                    'id' => 'mfn-post-subheader-image',
                    'type' => 'upload',
                    'title' => __('Subheader | Image', 'mfn-opts'),
                ),

                // options

                array(
                    'id' => 'mfn-meta-info-options',
                    'type' => 'info',
                    'title' => '',
                    'desc' => __('Options', 'mfn-opts'),
                    'class' => 'mfn-info',
                ),

                array(
                    'id' => 'mfn-post-hide-title',
                    'type' => 'switch',
                    'title' => __('Subheader | Hide', 'mfn-opts'),
                    'options'	=> array('1' => 'On', '0' => 'Off'),
                    'std' => '0'
                ),

                array(
                    'id' => 'mfn-post-remove-padding',
                    'type' => 'switch',
                    'title' => __('Content | Remove Padding', 'mfn-opts'),
                    'desc' => __('Remove default Content Padding', 'mfn-opts'),
                    'options' => array('1' => 'On','0' => 'Off'),
                    'std' => '0'
                ),

                array(
                    'id' => 'mfn-post-hide-image',
                    'type' => 'switch',
                    'title' => __('Featured Image | Hide', 'mfn-opts'),
                    'desc' => __('Hide Featured Image in post details', 'mfn-opts'),
                    'options'	=> array( '0' => 'Off', '1' => 'On' ),
                ),

                // advanced

                array(
                    'id' => 'mfn-meta-info-advanced',
                    'type' => 'info',
                    'title' => '',
                    'desc' => __('Advanced', 'mfn-opts'),
                    'class' => 'mfn-info',
                ),

                array(
                    'id' => 'mfn-post-link',
                    'type' => 'text',
                    'title' => __('External Link', 'mfn-opts'),
                    'desc' => __('for <b>Post Format: Link</b>', 'mfn-opts'),
                ),

                array(
                    'id' => 'mfn-post-bg',
                    'type' => 'color',
                    'title' => __('Background Color', 'mfn-opts'),
                    'desc' => __('for <b>Blog Layout: Masonry Tiles</b> & <b>Template: Intro</b>', 'mfn-opts'),
                ),

                array(
                    'id' => 'mfn-post-intro',
                    'type' => 'checkbox',
                    'title' => __('Intro | Options', 'mfn-opts'),
                    'desc' => __('for <b>Template: Intro</b>', 'mfn-opts'),
                    'options' => array(
                        'light' => __('Light | light image, dark text', 'mfn-opts'),
                        'full-screen' => __('Full Screen', 'mfn-opts'),
                        'parallax' => __('Parallax', 'mfn-opts'),
                        'cover' => __('Background size: Cover<span>enabled by default in parallax</span>', 'mfn-opts'),
                    ),
                ),

                // seo

                array(
                    'id' => 'mfn-meta-info-seo',
                    'type' => 'info',
                    'title' => '',
                    'desc' => __('SEO <span>below settings overwrite theme options</span>', 'mfn-opts'),
                    'class' => 'mfn-info',
                ),

                array(
                    'id' => 'mfn-meta-seo-title',
                    'type' => 'text',
                    'title' => __('SEO | Title', 'mfn-opts'),
                ),

                array(
                    'id' => 'mfn-meta-seo-description',
                    'type' => 'text',
                    'title' => __('SEO | Description', 'mfn-opts'),
                ),

                array(
                    'id' => 'mfn-meta-seo-keywords',
                    'type' => 'text',
                    'title' => __('SEO | Keywords', 'mfn-opts'),
                ),

                array(
                    'id' => 'mfn-meta-seo-og-image',
                    'type' => 'upload',
                    'title' => __('Open Graph | Image', 'mfn-opts'),
                    'sub_desc' => __('e.g. Facebook share image', 'mfn-opts'),
                ),

            ),
          );

            }
            
        public function register()
        {
			$labels = array(
				'name' => esc_html__('Videos', 'mfn-opts'),
				'singular_name' => esc_html__('Video', 'mfn-opts'),
				'add_new' => esc_html__('Add New', 'mfn-opts'),
				'add_new_item' => esc_html__('Add New Video', 'mfn-opts'),
				'edit_item' => esc_html__('Edit Video', 'mfn-opts'),
				'new_item' => esc_html__('New Video', 'mfn-opts'),
				'view_item' => esc_html__('View Videos', 'mfn-opts'),
				'search_items' => esc_html__('Search Videos', 'mfn-opts'),
				'not_found' => esc_html__('No videos found', 'mfn-opts'),
				'not_found_in_trash' => esc_html__('No videos found in Trash', 'mfn-opts'),
			  );

			$args = array(
				'labels' => $labels,
				'menu_icon' => 'dashicons-format-video',
				'public' => true,
				'show_ui' => true,
				'supports' => array('title', 'editor', 'page-attributes', 'thumbnail', 'excerpt'),
                'capability_type' => 'post',
			);

			register_post_type('video', $args);

			register_taxonomy('video-types', 'video', array(
				'label' => esc_html__('Video categories', 'mfn-opts'),
				'hierarchical' => true,
			));
		}

        }
    }

    new Mfn_Post_Type_Video();
}
add_action( 'after_setup_theme', 'mytheme_includes' );

Hello

I was trying to do the same thing and you helped me with add_action( 'after_setup_theme', 'mytheme_includes' );

For those using ACF Pro I made an "option page" under Betheme to select post types where you want to activate BeBuilder

/* Add BeBuilder custom post_type */
function load_cpt_builder() {
	if(!class_exists('Mfn_Post_Type_Custom')) {
		class Mfn_Post_Type_Custom extends Mfn_Post_Type
		{
			/**
			 * Mfn_Post_Type_Custom constructor
			 */
			public function __construct($post_type)
			{
				parent::__construct();
				if(is_admin()) {
					$this->fields = array(
						'id' => 'mfn-meta-'.$post_type,
						'title' => 'Builder',
						'page' => $post_type,
						'context' => 'normal',
						'priority' => 'high',
						'fields' => array(),
					);
					$this->builder = new Mfn_Builder_Admin();
				}
			}
		}
	}

	$cptx = get_option('options_bbcpt');
	if(!empty($cptx) && is_array($cptx)) {
		foreach($cptx as $cpt) {
			new Mfn_Post_Type_Custom($cpt);
		}
	}

	function custom_acf_cpt_choices($field) {
		$post_types = get_post_types(['public' => true,], 'objects');
		$post_type_list = array();
		foreach($post_types as $post_type) {
			if(!in_array($post_type->name, ['post', 'page', 'attachment', 'template', 'client', 'layout', 'offer', 'portfolio', 'slide', 'testimonial'])) {
				$post_type_list[$post_type->name] = $post_type->label;
			}
		}
		$field['choices'] = $post_type_list;
		return $field;
	}
	add_filter('acf/load_field/name=bbcpt', 'custom_acf_cpt_choices');

	add_action('acf/include_fields', function() {
		if(!function_exists('acf_add_local_field_group')) {
			return;
		}

		acf_add_local_field_group(array(
			'key'    => 'group_64e880538ce9f',
			'title'  => 'Options',
			'fields' => array(
				array(
					'key'               => 'field_64e87bcfab8cd',
					'label'             => 'Post types',
					'name'              => 'bbcpt',
					'aria-label'        => '',
					'type'              => 'select',
					'instructions'      => '',
					'required'          => 0,
					'conditional_logic' => 0,
					'wrapper'           => array(
						'width' => '',
						'class' => '',
						'id'    => '',
					),
					'choices'           => array(
						'documents' => 'Documents',
					),
					'default_value'     => array(),
					'return_format'     => 'value',
					'multiple'          => 1,
					'allow_null'        => 0,
					'ui'                => 0,
					'ajax'              => 0,
					'placeholder'       => '',
				),
			),
			'location' => array(
				array(
					array(
						'param'    => 'options_page',
						'operator' => '==',
						'value'    => 'builder_post_type',
					),
				),
			),
			'menu_order'            => 0,
			'position'              => 'normal',
			'style'                 => 'default',
			'label_placement'       => 'top',
			'instruction_placement' => 'label',
			'hide_on_screen'        => '',
			'active'                => true,
			'description'           => '',
			'show_in_rest'          => 0,
		));
	});

	add_action('acf/init', function() {
		acf_add_options_page(array(
			'page_title'  => 'Builder post_type',
			'menu_slug'   => 'builder_post_type',
			'parent_slug' => 'betheme',
			'redirect'    => false,
		));
	});

}
add_action('after_setup_theme', 'load_cpt_builder');
/* Add BeBuilder custom post_type */

Let me know if you have some ideas