Like others said, no interview or anything. Just walk up to the machine. If you go to an interview location, they will apply a sticker to your passport that will let you use the crew lines if the machines are down.

I just walked into the ATL customs office and they were able to verify I was cleared (swiped my passport) and stuck a sticker on. They did ask if I wanted to try a test machine, but I was running tight on time between flights, so I said no and was on my way.