I agree with the general sentiment in this thread.. just finish the book - it will be well worth it 
If you get overwhelmed when reading a chapter don’t be afraid to restart it/take a step back. Whenever I read a book I have a general rule that I make sure I understand everything as I am going and I do not proceed unless what I’ve read makes sense. If it doesn’t, I will re-read it or restart the chapter or even quickly skim through what I have read in the whole book just in case I forgot something. Most good books will usually build upon prior chapters ensuring you know everything needed to tackle what’s next in the book.
You might also want to read it concurrently with Programming Elixir - when I read them I felt they both complemented each other very well.
The tips on my blog might also help:
