Set-up: Find an assisted pull-up & dip machine. Keel or stand on the platform or foot bar ( depending on the machine design) and select the desired assistance weight - more weight equals more assistance. Assume an overhand shoulder width grip.
Lift: Bracing through your core, lift yourself up until your chin is over the bar, trying to get as high as possible. Cue yourself to pull your chest to the bar to ensure full height. Descend all the way to full extension as this will engage more of the shoulder stabilizers and muscle mass of the back - this will help in maintaining health in the shoulder girdle.
Emphasis: Do not swing your body up to the bar. The machine counterbalances body weight to make the movement more manageable. Repetitions are performed smoothly without bouncing or jerking.