There are 7 key stages to the golf swing. Popular golf coach, and Director of Coaching at The Sussex Golf Academy, Jerry Newham explains:

Address / Setup
Tilt forward from the hips, keeping the back straight and the chin up. Flex both knees with weight evenly spread between both feet. Arms hang freely under the chin. Active body, passive arms and hands.

Halfway Back
Left arm and hand swing club back on a slight inside path. Right arm folds. This will allow backswing position to be achieved creating width and depth. Shoulders fully turn along the same hip turn. Both knees stay flexed and poiting to the front. Toe of club should be pointing to the sky.

Top of Backswing
A correct position is achieved by swinging the left arm and hand. The right arm is passive but supportive. Shoulders should be fully turned 90 degrees and hips turned 45 degrees. The knees stay flexed with weight in the feet. Balance and body position / height should be maintained. Downward resistance powers the hands.

Downswing
The hands initiate the downswing which makes the body respond. The angle of the backswing is maintained through the downswing, allowing the club to be released just prior to impact, thus club head speed is created through the ball.

Impact Position
The club returns square to the target and is now able to extend forward along the intended line of flight. Note the shoulder line should be parallel to the club line just as in the setup but the hip is open. This creates space to allow us to swing through to our finish.

Extension Through Ball
The weight is transferred to our target side through the hip and foot action, this allows the arms, hands and club to be swung through the ball towards our target generating prolonged contact and most importantly the direction. Note the head remains still looking at the point where the ball was to allow backward resistance.

The Follow Through
The follow through tells us what has gone before. If we finish the swing in the correct position and are poised and balanced facing the target then we have completed the swing with a consistent flowing movement which must be repeated until it becomes automatic.