Focus on hitting the ball above your head, moving your hand upwards and outwards to generate topspin, and practicing the drills provided to develop the correct technique and feeling for the shot.
Very useful if you are trying to improve your topspin smash and hit it out of the court. Javier explains the progression from basic understanding to more complex movements. You will learn about the correct impact point above your head and how to generate topspin using your hand and body. Pay attention to the drills he uses, they are great for practicing the technique.