You do not really understand something unless you can explain it to your grandmother – Albert Einstein
The major emphasis in the CFI course is learning how to teach and how to develop and implement lesson plans, syllabus, and a library of training materials. During the ground school portion of the course you will compile together a personalized instruction manual for yourself (which you will use throughout your CFI career) and practice teaching each lesson required from a student pilot level to a CFI candidate. It is fun, but a demanding challenge that will teach you much about flying.
The ground school training for your CFI course is typically about 40-50 hours with your instructor, and about as much time of self study, preparation and practice on your own. Like we said, it is fun, but requires focus and dedication. And when it is over, it is tremendously rewarding feeling and a sense of achievement.