Hook the rope tensioner into the shackle.
Pull the free end of the guy through the rope tensioner until enough tension is achieved in the tower guy.
Release the free end of the guy.
The tension in the guy (in combination with friction of the rope riding on a pivot jaw in the body
of the rope tensioner) locks the jaws of the rope tensioner.
Jaw design is such that the greater the tension in the guy, the more the jaws grip the rope.
Apply tension to free end of rope and lift pivot jaw away from rope passing through the jaw zone.
Hold the pivot jaw in this position and move rope through the rope tensioner.