The M-System Bunkers series is all about throwing sand. The concept is hitting and throwing sand; you are not trying to hit the ball.
Next, Mike explains the idea that the ball goes where the sand goes. The clubface works the sand differently. Where the clubface is aimed isn’t where the ball will go.
Mike covers hand action, which is more of a level swing than an up-and-down action because you are trying to hit down and throw the sand.
Finally, Mike talks about setup and how you need to be stable and control your swing circle.
Distance, control of swing, uneven lies, how you set up, and how to use the club are other topics Mike covers in The M-System Bunker Series.