You can choose the selection mode using Product Selection Settings:
Mode 1: Restrict buyer to select only one of the above products (e.g. when selling similar products with different pricing plans or quantity).
On frontend, it will create a radio selection of list of products. You can choose any one of the products.
Mode 2: Allow buyer to select any of the above product(s) (e.g. when selling multiple products)
On frontend, it will create a checkbox with list of products. You can choose any product from the list
Mode 3: Force sell all of the above product(s) (e.g. when selling a fixed price bundle)
On frontend, it will show list of all the products without radio or checkbox
Note : – The settings will come into play when you drag “Products” Field in the form.