I have been officiating HS football for 6 years now. I try to work hard at reading the rules and case books relating to NFHS. I just purchased the Redding Study Guide and have done about 5 chapters - this is the best rule training book for high school football I have seen to date - a must for those still learning in my humble opinion! 
Yes, most here know about it, but glad you found it.
I have a t-shirt (that came from a dog rescue organization) that says it well: It doesn't matter where you came from as long as you wind up in the right place.