Your add 2 cart button product variants, checkbox options, total price, quantity selector are all handled by CommerceLab Shop Custom elements and will be displayd in the elements selection area popup just like all other elements. You will use these elements to initate to allow users to begin the purchasing process.
Make a product page as minimal or extensive as you'd like. The only element required is the Add 2 Cart element.
If you are on this page, we assume you have general knowelege of YOOtheme builder as outlined in this full tutorial or have used YOOtheme in the past. If you're new to YOOtheme you can start start from the beggining with the link is below.