All of the information within this guide can be found with the Lexica, holding the book in hand and holding CTRL will bring up the page about whichever item you are looking at. This will work with Botania items as well as Vanilla items will lead you to the Minecraft Wiki, Botania items will lead you to the page within the book. If you have JEI installed you can hold CTRL to find out more of that item, this will only work if you already know about this item. Holding shift with the book in hand and looking at Botania blocks will give you a short description of what that item does.
Later on, in the mod, you will unlock more and more information within the Lexica as you pick up new items or when you throw the book into a portal.