Wrap the yarn around the nostepinde, using the groove near the handle to catch the yarn.  Wrap it a few times to secure it.

Wind the yarn up the nostepinde, and then wind it a few more times around one spot in the center of the nostepinde.

Begin taking the yarn from the bottom of the wound yarns to the top, crossing from one side of the nostepinde to the other as you go.

Bring the yarn back down and then up again, laying it next to the wrap just made, continuing at an angle.  Rotate the nostepinde away from you as you need to in order to continue laying one wrap against the previous wrap.

A closer look.

A ball further along in progress.  If the ball begins to get too much of a football shape, stop and wind a few wraps straight around the top of the ball, and a few more straight around the bottom of the ball, then continue winding in the angled manner.

That's all there is to it!