If you've not done it before then I wouldn't get a rotary, a da polisher is a much better option as you don't have the risk of burning through the paint.
I'd clay the car first, you want to get rid of any containments in the paintwork before polishing. I've found that Menzerna polishes and pads work well on MK4 golf's, the combination of polish and pad depends on how bad the defects are.