Create Related Posts with Meta Box Plugin

template.php

<?php 
$field_id = 'related_posts';
$related_posts = rwmb_meta( $field_id );
if (isset($related_posts)) { ?>
	<div id="relatedPosts" class="related-posts">
		<h3 class="related-posts-headline"><em>You might also like</em></h3>
		<div class="related-posts-items jp-related-posts-grid"> 
			<?php foreach ($related_posts as $related_post) { ?>
				<div class="related-post-item">
					<a class="related-post-a" href="<?php echo get_the_permalink($related_post); ?>" title="<?php echo get_the_title($related_post); ?>" rel="nofollow">
						<img class="related-post-img" src="<?php echo get_the_post_thumbnail_url($related_post, 'thumbnail'); ?>" alt="<?php echo get_the_title($related_post); ?>">
					</a>
			    <h4 class="related-post-title">
				<a class="related-post-a" href="<?php echo get_the_permalink($related_post); ?>" title="<?php echo get_the_title($related_post); ?>" rel="nofollow"><?php echo get_the_title($related_post); ?></a>
			    </h4>
			    <p class="related-post-excerpt"><?php the_excerpt($related_post); ?></p>
			</div>

			<?php } ?>
		</div>
	</div>	 
<?php } ?>