WordPress - ACF custom forms

acf-backend-form.php

<?php
require_once 'acf.php';

add_action('admin_head', function () {
	do_action('acf/input/admin_head');
	acf_form_head();
	wp_enqueue_media();
});

add_action('admin_enqueue_scripts', function () {
	wp_enqueue_script('acf-input');
});

\Timber::render( 'backend-form.twig', null );

acf-backend-form.twig

<div class="wrap">
    <form method="post" action="">
        {{ fn( 'acf_form',     {
            'field_groups': [ 'acf_tracking_mapping' ],
            'form': false,
            'post_id': 'mypageid'
        }) }}
        {{ fn( 'submit_button' ) }}
    </form>
</div>

acf-form-fields.php

<?php

register_field_group(array (
	'id' => 'acf_tracking_mapping',
	'title' => 'Tracking array mapping',
	'fields' => array (
		array (
			// Put some fields here
		),
	),
	'location' => array(), // Won't appear anyway
	'options' => array (
		'position' => 'normal',
		'layout' => 'no_box',
		'hide_on_screen' => array (
		),
	),
	'menu_order' => 0,
));