the ID for each item is the same.
the cart usses the ID as a unique identifier.
on the shop page, next to the quantity text box for each add to cart button is the hidden form element that passes the id.
select each one of those hidden form elements and set the initial value to the ID for that products.
you can use the recordset column since you do not have a repeat region. you are creating static add to cart buttons, so will need to set the ID statically.