Each place will work, as Dadguy explained, but I preferred the pool nearest to the linking book myself. I just saved my game when I saw the guide there and then reloaded until I succeeded.

I just finished the game. I really enjoyed it and want to thank you for the help.
Lady K, the pool you used ended up working best for me too. I had to reload a few times as well.
And I was almost ready to call it quits in the dream puzzle, but finally found my way through that too.
Great game.