Reach up and grasp bar with wide overhand grip.
Pull body up until neck reaches height of hands. Lower body until arms and shoulders are fully extended. Repeat.
Range of motion will be compromised if grip is too wide.
To decrease difficulty, use assisted machine, assisting partner, or self assisted by placing feet on bench or floor under bar.
Added weight can be placed on dip belt or dumbbell can be placed between ankles to increase intensity.