The rest of the books build upon this foundation. You can read them in whatever order speaks to you the most. There is no correct order, no wrong order.
Unfortunately, an in-depth study of the Faerie Faith requires one-on-one training with a teacher, and cannot be done long distance, or even over email. Also, living close by does not guarantee acceptance as a student - the one Faerie Faith coven is currently closed, and not accepting any more students. We're working on turning out some more teachers, but it will take a few years for their training to be complete. In the meantime, read, read, read!