Just bought $5 of Bitcoins from CoinBase. How do I spend them? I gather it has something to do with QR codes. . . .
don't worry -- they're there for convenience only.
Scanning the QR code helps reading either a public key (to verify) or your private key (to spend your bitcoins) into whatever application you are using to verify or spend from your balance respectively.
Copy-and-paste works as well, doing the same for you as those QR codes you see everywhere...