Question for you experts

I am pretty much at the beginning of the game. I have arrived at Arkhamend, spent the night and I am now at the bookstore. I found the book and I need to unlock it.
The WT talks about listening for clicks. I have the stethascope attached to the book, but the only time I hear clicks when when I lock the key into place after rotating wheels. But, I have NO clue what I am supposed to be doing. There seems to be no pattern to what wheels I am supposed to be turning and how many turns. It could take weeks before I accidently hit on the right combination.
Can anyone help or do I need a saved game for after the book is unlocked?
Thanks!