I would like t change the number of Products per Page. I've found your post in internet where you suggest to insert this code:

"add_action( 'after_setup_theme', 'change_parent_products_per_page', 10 );
function change_parent_products_per_page() {
   //chnge how many products are displayed per page    
    add_filter( 'loop_shop_per_page', create_function( '$cols', 'return 60;' ), 20 );
}"

but it not work.
Can you help me?

Silvia