During the very start of the backswing, it is the initial shift of the body to the right side that defines whether or not the resulting downswing and eventual follow through are executed correctly.

It's a carefully intermixed chain of actions and reactions.

Moving back slowly but not too slowly, just before the body turns at the waist and the club is lifted back in a wide arc, the weight should be slanted slightly over to the right foot so that the recoil of the downswing delivers sufficient power to the ball.

It's a question of good balance, transfer of body energy at the right moment, and of course perfect timing.