It appears to be a custom grid code added to front-page.php
An easier way would be to install a plugin like this ...
https://wordpress.org/plugins/plugin-reviews/#description.
Configure it as a grid and how many reviews to display. There may be options to only use reviews with photos. Not sure.
... and add the second line of code below with the
shortcode pasted in the middle of it here at the bottom of front-page.php in between the content and the footer code lines.
<?php get_template_part( 'content' ) ?>
<?php echo do_shortcode('
[SHORTCODE HERE"]');?>
<?php get_footer() ?>
No promises ... I haven't tried this. Just make a backup of front-page.php ... edit another copy and upload via FTP or Cpanel/File Manager.
Just try it and let us know how it went.
Better to do this in a child theme so the edits don't get over written with theme updates. But for experimental purposes, don't bother unless it works.
Alternatively ... write to support and ask them how they did it. But they may not want to give their secrets away, they haven't answered here yet. ... LOL