How to Purl
With the yarn at the front of the work, insert the tip of the right needle from right to left through the front of the first stitch on the left needle.
Wrap the yarn from the right to left under the tip of the right needle.
Pull the yarn back through the stitch, forming a loop on the right needle.
Slide the stitch off the left needle.
To purl the entire row, repeat Steps 1-4 until all of the stitches are transferred to the right needle.
Turn the work and place the needle with the stitches on it in the left hand to start the next row.
Purling every row is also considered garter stitch and makes ridges on both sides of the knitted fabric. Purling is most often used with knit stitches.