This is a great movement to use as a warm-up because it activates the nervous system without overly fatiguing the body. It also teaches you to jump with a weight in your hands, as with Olympic-style lifts.
The movement with the legs should be very fast and explosive. Use a powerful hip action.
The arm with the dumbbell should stay close to the body as it rises.
Remember, while you do pull with the arm, it's the movement created by your lower body that gets the dumbbell overhead.
Thibs is a sadistic SOB because he's always glad to bring more pain your way. This time the red glow of his laser sight is dancing around your chest and he's ready to pull the trigger.