Hi,
I can see that you have a listing of products on that link with an associated products listing attached to it. So it seems to do what you want except that you have the products displayed twice. You can just go in the menu Display->Content menus, edit your menu and disable the module in the associated modules option there in order to avoid that.
In the Files tab of the configuration, you can configure the size of the main product page on the product page as well as the default thumbnails size for listings.
If you want to have only a products listing module on your page, then you should create a menu item of the type joomla article and potentially include a products listing module in your article with the loadposition plugin of joomla:
docs.joomla.org/How_do_you_put_a_module_inside_an_article%3F