Add pagination to custom page

You need to set up query for pagination, look at this example :

$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

$args = array(
    'post__in' => $ids,
    'post_type' => 'product',
    'paged' => $paged,
    'posts_per_page' => 15);

query_posts($args);