You just go to the membership desk and let them know the name you ordered under.
They get a paper with your order and they scan your membership card and then a barcode on the paper and the order loads into the register. Then you pay right at the membership desk.
The order is already in a cart ready for you to go locked up in “the cage” which someone gets out while membership is taking care of your payment.
IF you already paid online—you still stop at membership to pick up your receipt.