Right now, Gift Cards can ONLY be used upon Enrollment into a Program. In the future, we have plans to expand the uses.
On the Enroll page, before completing Enrollment, the Gift Card credit will show (as well as any other credit on the Account).
Previous credits on the Account will be used BEFORE any Gift Card credit. The gift card balance will be automatically applied, but only the applicable amount will be used (after any other credits are applied).