Modify a query to show an archive of CPTs

archive-cpt.php

<?php
add_action('pre_get_posts', 'ipstenu_pre_get_posts');
function ipstenu_pre_get_posts($query){
	if ($query->is_page('name-of-your-page')) { // any and all conditionals work here as a method of the $query object
		$query->set('post_type', 'video'); // use the set method as if you were using a regular WP_Query or query_posts etc...
		$query->set('posts_per_page', 10);
	}
}