View - E-Commerce - Edit Website - Content - Product Selection - Items in your Webshop
By clicking on Items in your Webshop, a window will pop up where you can easily administer which of your products you want to be available in your webshop.
You do so by highlighting the products in the above list and then moving them to the bottom window by clicking on the arrow-buttons. The items available in your webshop are those displayed in the bottom window.
Read more about: