I really like this formula for writing nonfiction series recommended by Roger C. Parker. (I’m sorry, I’ve lost the link to his original article.) He claims that this formula has been very successful for him. He calls it the 3-Act Structure. I have used this structure myself without having given it a name.
The 3-Act writing formula is especially appropriate for information that is focused on teaching new skills. Parker breaks down the 3-Acts this way.
Act One contains a series of scenes (chapters if you please) related to getting started. The first chapter would provide an introductory perspective that gives readers an oversight of how they will benefit from the information that the book is going to cover. This Act can then be filled out with additional information that is introductory in nature.