Product Association
Make sure you’ve created a group before adding products.
Adding a new product to your Access Group
If you’ve just created a group, or are returning to view an existing one, you should be directed to the products list by default. To verify which tab you’re on, check the navigation to see which is greyed out, or look for an “Add Products” button on the right. If it’s there, you’re good to go, and can start managing the access group’s associated products:

Managing API Products associated with an Access Group
After clicking the Add Products button, you’ll be directed to a page with a list of API products on the left and your selected products on the right. The UI should feel extremely familiar to Team/Developer app creation. Simply add or remove your desired apps to and from the right column. Once you’re done, save your selection.
Create as many Access Groups as you want with as many configurations as you need, easily controlling which users are granted access to any number of APIs.