I'm not sure what the one step is, but after the buffing I would use a finisher/polisher like Finesse It. Then wax. I'd do the buffing and polisher with a buffer and wax by hand. I'm sure others have don't it differently, but the wax is a protector, not a finisher that needs to do "work." It just needs to be applied, and sometimes a buffer can actually burn the wax off and not leave it applied.
Looking great, and again, you're making great progress.