The register will tell you everything you need to do. If at no point does the register tell you to scan a gift card after you press total then the guest does not qualify. It will also say while you’re scanning underneath the item. For example say you have to buy 3 tides to get the gift card, after you scan the 3rd tide it will say “buy 3 get $5 giftcard” underneath all the tides on the screen. You can also press the price inquiry button on the register, scan the item and it will tell you if it qualifies for any gift card offers.