Go into the store you shopped at on the app at the top you'll see how to redeem upload only, link card/account only or both if both you can only pick one. Click the offers you want to buy 1st then go buy them after go back into the store it will say redeem on the bottom click it and follow the prompts.
@Kathy21 If you shopped at a store that allows scanning the receipt (some receipts are linking your card only). Make sure all your offers are selected. Tap on redeem at the bottom, then select the store you shopped at - and choose "use receipt". you may also see "link account", this should be done BEFORE shopping and using your rewards card.