How do you read a codex?

Answer 1

The most obvious suggestion is the best here, pick it up and read it start to finish. It shouldn't take too long, as there is a lot of stuff you can skip upon first reading (Background, technical stats) which you will only need later. Then once you've done that you'll have a good idea as to how your army's codex is laid out, so you know where to look for information when you need it.

Answer 2

You have to find amd synchronize at viewpoints, then codex page locations will open up on your map.

Answer 3

if u mean the Assassins Creed 2 codex NO by any other means i don't know :D