The gun is charged, and the workpiece is grounded, so the powder is attracted to the work piece. After you coat it, you bake it for 20 minutes and it's done.
I coated the throttle perch, then realized I forgot to mask the threaded holes. Since I hadn't baked the part, I simply blew the powder off it, masked the holes, and re-sprayed.
It's a very cool process, now I'm looking for more parts to treat...