Add related content as a UL. Data comes form the "Relationship" field type in the WordPress Advanced Custom Fields plugin, return format set as "post objects". Hook code is for Thesis 2.1 WP framework.

ACF related content ul

/**Add related content**/
function add_related_lessons(){

  $posts = get_field('related_lessons'); // the repeater field name
 
    if( $posts ): ?>
      <h3>Related Video Lessons in this Series</h3>
      	<ul>
      	<?php foreach( $posts as $post_object): ?>
      	    <li>
      	    	<a href="<?php echo get_permalink($post_object->ID); ?>"><?php echo get_the_title($post_object->ID); ?></a>
      	    	
      	    </li>
      	<?php endforeach; ?>
      	</ul>
    <?php endif;
}

add_action('hook_top_related_lessons','add_related_lessons');