It looks like this is the one - http://joann.lionbrand.com/patterns/80405AD.html
You need size 13 needles straight or circular and you knit it flat and seam up when you're done.
CO 44 sts, k 2 row. Then starting with a knit row work in stockinette st (knit one row, purl one row) for 28 rows. The next row you knit 2 tog on all sts. Then cut the yarn with a long tail and thread it through the sts on the needle like a drawstring and use the rest to sew the edges together.
What part don't you understand?