Backswing:

Once the set up is complete the swinging part of the golf swing begins.  This is called the back swing.  A good back swing sets the swing up for success.  A reliable back swing will lead to a consistent, repeatable golf swing.  Here are the positions of the back swing.

The start of the back swing is critical.  The first two feet off the golf ball must be done in a controlled manner.  That doesn't necessarily mean slowly, just controlled.  The personality of the individual will dictate how fast or slow the swing begins.  I will tell you that in my experience slower leads to a more consistent backswing. 

The arms move the club away from the ball.  At two feet away from the golf ball the arms are completely straight.  The next step is the set.  The set is a hammer-like motion between the shaft of the club, the right wrist, and left arm.  The set turns a one-lever swing into a two-lever swing which provides an enormous power boost.