The 4 anchors he was talking about refer to the way you hold the bow at full draw. If you have consistent anchors, you will be able to hit consistently. It's just like with your shotgun, if you mount the gun differently, you won't hit the same place. Same same here. Archery is mostly mechanics, and the more consistent you anchor the better you will become.

Anchors come in several forms.
1. The string touching the tip of your nose
2. The peep site is an anchor
3. Your nuckle on your jawbone

And there are several others. Understand?