The plugin adds the dedicated “Product Add-Ons” section in each product editing page through which you can manage the view of the add-ons for the related product.
If you want to edit one of the options groups created with general rules, click on the “Manage all groups” button.
If you want to disable the global add-ons on the product, you must enable the “Disable globals” option.
Insert the group name and click on the “Add group” button to create an options group associated only with the selected product.
Now you can follow all the directions that you find on this page of the documentation.
The plugin allows creating options groups for variable products, but not for single product variations. The options group can be configured in the general product information and not in a different way for single variation.