You need to click them in order and one of them requires three clicks. Check every one of them out and click on the flags behind them that say "The Order." Doing so will trigger clues. The books and the gems they are holding are all the clues you need to figure it out (regarding the gems, pay attention to the order they glow). The gems correlate to the symbols on their chests. As a hint, start with the goat holding the book with "I" and end with the bull holding the book with "The End."