You're going to create a hem for some of the sts by purling from top and bottom needles held in the left hand onto the right-hand needle. It's like this
tutorial except that you're using two needles to hold the sts instead of a needle and a crochet hook. At about 5.5 minutes into this video
there's a demo of the point you're at with row 6. She's knitting onto the right needle but you'll be purling.