Michael on "Result on columns"

Hello everyone!
I state: I do not know well the php code. I want to know how to bring up the results of this query (!?) On two or more columns. Thanks so much!

<?php if ( has_post_thumbnail() ) { echo '<a href="'; the_permalink(); echo '">'; the_post_thumbnail("thumbnail"); echo '</a>'; } ?>

please post the full code of the template.

as you will probably need to apply CSS to the individual links, it would be useful if you add a CSS class to the link tag.