I started by attaching the sleeves to the bottom panels and connected the upper panel last; in retrospect I'm not sure this was the best order because I found this last step very difficult. The sizes of the tops of the sleeves and the openings on the upper panel just didn't seem to line up, and I spent of lot of time re-pinning the pieces together. I will admit my order was just going off of what my original shirt looked like, and I didn't research the proper way to attach rounded things.