In knitting patterns, sometimes you will see the instructions "pick up x stitches" and sometimes "pick up and knit." The terms are often used to mean the same thing. Once you have picked up the stitch along the edge of your work, you have to knit it in order to make it look like a normal, workable stitch.
This can be accomplished using just one needle, or you can pick up the stitch with one needle and knit it onto the other needle, whichever is easier for you. Some people also use a crochet hook to help pick up stitches and pull the working yarn through. If you do this, all you have to do is slide the loop from the hook to the needle and you've got a completed stitch.