You pick up the stitches with the right side facing. Start at the underarm and work your way around the sleeve opening. That's the easy part.
As for the short rows, I wish I could tell you to do X,Y, and Z to get a perfect sleeve top, but I wouldn't want to mess it up. If I were doing it, I'd have to experiment, to be honest. That's why 'cheating' off other patterns is helpful. Someone else has already done the work.