Remake of single advert

Hi,
you can redo the whole wpadverts/templates/single.php template file by creating a child-template as explained here https://wpadverts.com/doc/child-themes-and-templates/

That being said if you only want to move the gallery to the bottom of the page you can do that by adding the code below in your theme functions.php file

add_action( "init", function() {
  remove_action('adverts_tpl_single_top', 'adverts_single_rslides');
  add_action('adverts_tpl_single_bottom', 'adverts_single_rslides', 1);
}, 1000 );