This is the first book of its kind for US flight training. It tells you specifically what to say when you are demonstrating flight maneuvers to students. CFI applicants always say that they get good at presenting the pre-flight lesson plan briefings on the ground, but struggle with what to say, what to show in what order etc. while in flight.
The way to use this book it to practice it by chair flying or getting into a simulator. You need to be able to bring out the key points while the maneuver is being demonstrated and the timing of the things to say should then be said at the right times as the maneuver goes on.
Some people find it very useful to take printed copies of this book or and iPad version in the airplane to review as a reminder and then after the demonstration as a checklist to see that all of the points were said.