How to add a menu in the footer of OnePress WordPress Theme via child theme

functions.php

<?php
/**
 * OnePress Child Theme Functions
 *
 */

/**
 * Enqueue child theme style
 */
add_action( 'wp_enqueue_scripts', 'onepress_child_enqueue_styles', 15 );
function onepress_child_enqueue_styles() {
    wp_enqueue_style( 'onepress-child-style', get_stylesheet_directory_uri() . '/style.css' );
}

// !!! Replace everywhere 'onepress-child' with your Text Domain's theme
// if you have changed it in your child theme (see style.css header).

function wp_custom_new_menu() {
    // Add two menus: this theme uses wp_nav_menu() in two locations.  
    register_nav_menus( array(  
      'primary' => __( 'Primary Navigation', 'onepress-child' ),  
      'secondary' => __('Secondary Navigation', 'onepress-child')  
    ) );   
}
add_action( 'init', 'wp_custom_new_menu' );

// Customize the footer area (show also the secondary menu)
if ( ! function_exists( 'onepress_footer_site_info' ) ) {
    /**
    * Add Copyright and Credit text to footer
    * @since 1.1.3
    */
    function onepress_footer_site_info()
    {
     ?>
     
     <!-- shows our custom menu -->
     <?php if( has_nav_menu( 'secondary', 'onepress-child' ) ) {
         ?> <div class="footer-menu-container"> <?php
         wp_nav_menu( array( 'theme_location' => 'secondary' ) );
         ?> </div> <?php
     } ?>
     <!-- end: shows our custom menu -->

     <?php printf(esc_html__('Copyright %1$s %2$s %3$s', 'onepress'), '&copy;', esc_attr(date('Y')), esc_attr(get_bloginfo())); ?>
     <span class="sep"> &ndash; </span>
     <?php printf(esc_html__('%1$s theme by %2$s', 'onepress'), '<a href="' . esc_url('https://www.famethemes.com/themes/onepress', 'onepress') . '">OnePress</a>', 'FameThemes'); ?>
     <?php
    }
}

style.css

/*
 Theme Name:   OnePress Child
 Theme URI:    https://www.famethemes.com
 Description:  OnePress sample child theme
 Author:       FameThemes
 Author URI:   https://www.famethemes.com
 Template:     onepress
 Version:      1.0.0
 Tags:         light, dark, two-columns, right-sidebar, responsive-layout, accessibility-ready
 Text Domain:  onepress-child
*/

/* Styles for the custom footer menu
-------------------------------------------------------------- */

.footer-menu-container { display: block; width:100%; margin-bottom: 12px; }
.footer-menu-container ul { display: inline; padding-left: 0px; }
.footer-menu-container li { list-style-type: none; display: inline; }

.footer-menu-container li:before {
	content: "\007C";
	font-family: FontAwesome;
    margin-left: 6px;
	margin-right: 8px;
}

.footer-menu-container li:first-of-type:before {
	content: none;
	margin-right: 0;
}

.footer-menu-container li:last-of-type {
	margin-right: 0;
}

/* Add your custom css below
-------------------------------------------------------------- */

Read more in the article: https://lorepirri.com/onepress-wp-theme-add-footer-menu.html