Create pack of products

[martinab]

I should create 3 packages, each of 3 existing products on a site in prestashop 1.6.1.17

Since my products have two variants related to packaging, I have duplicated the products and eliminated the combinations in order to create packages.

After this operation I moved to the product / package creation page, but if I click on the radio button the alert "You cannot use combinations with pack" appears and the selection stays on "standard product"

Can anyone tell me if I have to enable packages first or if I have forgotten some passages?

Thank you!