If you were to pick up a weight from the ground and lift it over your head, you would use exactly half of the functions of the shoulder. That might be called a snatch. The snatch is a combination of what we call a lift and what we call a press.

Lift A

Shoulder Blade Part of Lift A

Press

The press movement is best learned by using the body as resistance and culminates in an elbow or handstand. Progress in order, starting with the wall press.

If you pay attention, you might notice the guy who wins this competition is the only one who does it correctly. After practicing your presses, you might see it clearly.

Wall Press

Floor Press

Couch Press