1. Open container2. Get posts that this post's category is3. Posts per page4. Display other posts that aren't this post5. For every post in this query, display certain meta info (inside <li>)6. Reset post data

single.php

<!-- Custom Related Posts -->
		<div class="single_related-posts"> 
			<?php  foreach((get_the_category()) as $category) : ?>
  				<h3>Browse more <?php echo $category->name; endforeach;?></h3>
				<ul>
		<?php

		$related = get_posts( array( 
			'category__in' => wp_get_post_categories($post->ID), 
			'posts_per_page' => 6, 
			'post__not_in' => array($post->ID) ) );

		if( $related ) foreach( $related as $post ) {
			setup_postdata($post); ?>
		
			
				<li>
					<a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title(); ?>">
						<?php the_post_thumbnail(); ?>
					</a>
				
				</li>
			
		 
		<?php }
		wp_reset_postdata(); ?>
			</ul>
		</div>