Unravel about 12 inches of yarn from the ball. Pull the end of the yarn through the spool so that the end is opposite to the notches at the top of the spool.
Start by taking the yarn around the outside of one notch. Cross the yarn over to the next notch, and go around the outside of this notch. Repeat this step for all subsequent notches until you loop back to the starting notch.
Wrap the yarn around the starting notch for a second time, and pull the yarn toward the next notch. Using the needle, pull the first loop of the notch up and over the yarn and the top of the notch. Gently tug on the yarn to make the stitch taut. Repeat this step for the subsequent notches until a woven cord starts to form at the bottom of the spool.
After the cord reaches the desired length, take the stitch off the first notch, and put it around the second notch. Pull the second notch's stitch up and over the first notch's stitch, and move the second stitch around the third notch. Repeat this until the last stitch remains, then cut the yarn. Pull the end of the yarn through the last stitch, and take it off the notch. Yank on the end of the yarn to make it taut, then push the end through the cord using the needle.