Knitting tutorial | The purl stitch
With the yarn at the front of your work, insert the right needle in the first stitch of the left needle from right to left.
Yarn over wrapping the yarn around the right needle.
With right needle, draw yarn through the stitch:
Slip this new stitch on the right needle. Repeat these steps for each of the stitches on the left needle.
If it's not already done, I suggest you to learn the knit stitch. You can also learn the purl bind off to close your work.