Scroll down on this page for the three-needle bind-off. That's what the first part of your pattern is calling for. It makes a lovely shoulder seam.
Then, because the cuff is folded up and you want the seam on the other side, you'll flip your knitting so it's right-side out and continue working the 3nbo with the inside of the knitting facing so the seam will look nice when you fold it up.
When you join the other seams, use the Mattress Stitch, working this with the outside of the sweater facing you until you get to the end where you'll work the seam on the inside so it will look good when you fold it. http://www.knittinghelp.com/videos/knitting-tips