To begin installing the Denver Boot, first spread the clamp open and slide over the tire onto the rim. Both edges of the clamp have groves that are designed to fit on the lip of the rim. The spring on the inside of the clamp will hold the clamp in place until the next step.

Turn the boot wrench clockwise to tighten the bolt. When the bolt is tightened the clamp squeezes itself securely to the rim.
Slide the angled end of the arm into the slot on the clamp. Note that when the arm is swung forward, the bolt head is secured on the inside of the arm.
Take the hub cover and hold it against the face of the rim. Swing the arm over the clamp making sure that the bolt on the hub cover goes into one of the holes on the end of the arm.
Insert the padlock in the closest open hole to the edge of the arm. Tip: the lock will be much easier to remove if you put it on upside down with the keyhole facing up. Do not do this during freezing weather as melting snow might freeze the keyhole closed.
The final step is to turn the boot wrench counter clockwise to apply pressure between the boot hub and the arm. The Denver Boot is now securely attached to the wheel and the vehicle is immobilized.