The Hammer of Below

The first thing you need to do to start to be able to do the collection is inspect a chest at -101, 45, -80. After you have clicked that chest (no quest, seems to be a flag on your character) you can harvest a book in the small cave under the waterfall. Getting the book starts the collection quest. You can now see pages for the book all through kaladim. Pages seem to be linked to a certain geographical region. For example page 1 I have seen in the same cave where you get the book and no where else. Also I have never seen a page besides page 1 in the cave.