I know that videos are a great way of watching the technique of a player, but sometimes these photo slides are even better.

If we call the top row 1-5 and the bottom 6-10, you can see clearly in 2 how Andy M starts to turn those shoulders.In 3 look at the use of the non racket hand to assist the take back, and also of course helps with the shoulder turn.

In 4 the weight is starting to load on the right side, and the non racket hand is helping to track the ball to the point of contact.
6 shows the wrist lay back to about 7 o'clock and 7 shows how he has dropped the racket below the ball to encourage lift and hence top spin.

8 shows the point of contact - out in front of the leading hip, and 9 the weight starts to transfer to 10 the left foot.In 10 as well you can see how the racket has rotated through 180 degrees from photo 6.Shoulders have turned nicely and the elbow of the hitting arm is pointing back down the court.

Nice shot!