For receipt upload, you need to claim the offer first, then you have 4 hours to make your purchase after claiming the offer. After 4 hours, the offer you claimed expires and is no longer valid. You have 24 hours to upload the image you took of the receipt, and you'll be notified when the offer has processed!
For Check In offers, click here.
Yes, it's a lot of numbers, but when done correctly, they'll all add up to your cash back! ;)