@Maria-12648430 was just joking (or so I think, you never know with her 
), and as for myself, I’m not saying Francescos book is bad 
It’s really great, but from what I see I’d say it isn’t the best for you at this point.
Look at it this way: You’re currently trying to understand meta programming (apply etc), something that is both quite advanced and that you will probably never need in the foreseeable future. At the same time, you are struggling (or maybe better, are not comfortable with) the matching operator (=) which is an absolute basic building block, something that you will absolutely need countless times of every day for the rest of your Erlang life 
(No offense btw, I just have a feeling that your current approach will ultimately lead only to frustration, and even if it doesn’t, you could have progressed much faster and easier 
)