I see what Knitting Guy is saying. If you knit English (holding the yarn in the right hand), you start with the yarn in front because you just did a purl and then like he said wrap the yarn around the right hand needle like you would to purl. Do that before you stick the RH needle into the stitch you are going to purl. Then purl the stitch.
If you knit Continental, after you purl the first stitch bring the yarn over the top of the RH needle to the back, and continue on around until you have the yarn back in front again. Then purl the next stitch.