Hi Chifilo, nothing's actually missing: the map and encyclopedia are the "introduction" part… It's just bits and pieces you don't have to use. I'd say the best way to start would be to pick any of the 15 adventures relying on its complexity, themes… maybe there's one that would fit easily in your ongoing campaign, or there might be some extras you can't wait to roleplay!
We're discussing the possibility to open a discussion part on this page where we could chat about the adventures and have a Q&A, but in the meantime feel free to contact the author @JanVanHouten and myself @nicolasfolliot on Twitter.