While walking around, you may find blue books laying on the ground. If you find one, pick it up with . Then when you see a 3x3 square of hieroglyphics, walk up to it and press . The game will show you a short sequence on the glyphs. Then move your cursor around and select the glyphs with in the order you were shown. If done correctly, the wall will open. Repeat 49 more times for unlocked goodness. There are also characters who come already set with a book. To check to see if a character comes ready with a book, press to see what they're carrying.
If you're looking to get this in a hurry, play "Temple of the Grail" in Free Play mode, as there are 2 puzzles right in the beginning room of the level.