First check how much air pressure you are currently running in your fork. WRITE IT DOWN! This is your preferred sir pressure.
Next, let all the air out of your fork and remove the whole air cap assembly on the top left leg of your fork.
Then, thread your new RUNT into the top left leg of your fork using the appropriate size socket wrench.
Air up your RUNT, starting with the HIGH chamber and then the LOW chamber as outlined below.
First, pump up the HIGH chamber of your RUNT to 2x your preferred pressure.
Next, pump the LOW chamber of your RUNT to your preferred pressure.
Preferred pressure = 60
High Chamber = 120
Low Chamber = 60
WRITE IT DOWN!
Make adjustments in 2.5-5 psi increments, keeping the 2:1 ratio between High Chamber and Low Chamber. Like a coil spring a small change in the initial makes a big difference throughout the stroke.
If you need to increase your bottom out resistance, increase only the High Chamber in 5psi increments.