Show all unit modules in single unit page

code.php

<!-- This code should be placed in single-unit.php of your child theme -->

<div class="custom_unit_details">
<?php

    $unit_class = new Unit( get_the_ID() );
    $unit_pagination = cp_unit_uses_new_pagination( get_the_ID() );

    if ( $unit_pagination ) {
        $unit_pages = coursepress_unit_pages( get_the_ID(), $unit_pagination );
    } else {
        $unit_pages = coursepress_unit_pages( get_the_ID() );
    }
?>
<ul>
<?php
for ( $i = 1; $i <= $unit_pages; $i++ ) {
        
                ?>
                <li class="course_structure_page_li <?php echo $existing_student ? 'single_column' : ''; ?>">
                        <?php
                        $pages_num	 = 1;
                        $page_title	 = $unit_class->get_unit_page_name( $i );
                        ?>

                        <label for="page_<?php echo get_the_ID() . '_' . $i; ?>">
                                <?php
                                $title		 = '';
                                if ( $existing_student && $enable_links ) {
                                        $p_title = isset( $page_title ) && $page_title !== '' ? $page_title : __( 'Untitled Page', 'cp' );
                                        $title	 = '<a href="' . trailingslashit( $unit_permalink ) . trailingslashit( 'page' ) . trailingslashit( $i ) . '">' . $p_title . '</a>';
                                } else {
                                        $title = isset( $page_title ) && $page_title !== '' ? $page_title : __( 'Untitled Page', 'cp' );
                                }
                                ?>

                                <div class="tree-page-left">
                                        <?php echo $title; ?>
                                </div>
                                <div class="tree-page-right">

                                        <?php
                                        if ( isset( $preview_page[ get_the_ID() . '_' . $i ] ) && $preview_page[ get_the_ID() . '_' . $i ] == 'on' && $unit_permalink && !$existing_student ) {
                                                ?>
                                                <a href="<?php echo $unit_permalink; ?>page/<?php echo $i; ?>?try" class="preview_option"><?php echo $free_text; ?></a>
                                        <?php } ?>

                                </div>
                        </label>

                        <?php ?>
                </li>
                <?php
        
}//page visible
?>
</ul>
</div>