Welcome to Knitting Help!
You're getting a little ahead of yourself here. First get the materials and practice knitting till you feel comfortable with it. Then you can learn to purl and practice that.
I suggest you get some size US 8 needles (bamboo are good to learn) and some soft, smooth, light colored yarn in a medium weight like worsted. It has a 4 on the label. Don't get anything fuzzy like novelty yarns. They are hard to learn with.
There are videos here on the video tab and if you have trouble just ask.