I really like the idea behind your book, and I appreciet a lot you open-sourcing it [I'll make sure to get a physical copy nonetheless ;-) ]

I constantly struggle with organising and reorganising my backup procedure, and I imagine how difficult and hopeless may seem to people starting with it. It's true that the internet contains all the information you need (and even more), but a distillate of said information in the form of a book with exercises is sometimes the best way to start approaching something complex.