The nocks are called tunable because you can twist them into the position you wish to have your feathers set.
You want no or a little feather contact with the rest, shelf,or whatever you are shooting off of.
You just turn them in the direction you want adjust, shoot, and then readjust. I personally don't like them, and prefer the nock adapter that they use to come with. I have shot them long enough I know how to position my feathers. I hated them on the Arrow Dynamics too, for the same reason.