Display related posts in template

It would be helpful if you could provide a little more detail. Could you send a link, and help us know what you have now as well as what you’re trying to achieve?

well I just want to add it as php
with title(not linked)
and my custom thumbnail size

Kind like this

<?php the_title(); ?>
<a  href="<?php echo wp_get_shortlink(); ?>">
	<?php the_post_thumbnail( '350xXXX' ); ?>
</a>