Use this site for the solutions to all the puzzles, this link goes to the first ten puzzles (the puzzles are numbered by how many you've collected) but there's a link to the next ten at the bottom of the page.
http://mycheats.1up.com/view/section/3170852/27934/assassin_s_creed_2/xbox_360 --- Yoda of Borg are we: Futile is resistance. Assimilate you, we will.
This is taken word-for-word from my guide, which worked for me...
1.) Rotate Ring 5 (linked to Ring 2) five notches to the right 2.) Rotate Ring 3 (linked to Ring 4) two notches to the right 3.) Rotate Ring 4 (linked to RIng 1) five notches to the right 4.) Rotate Ring 2 five notches to the left 5.) Rotate Ring 1 (linked to Ring 5) one notch to the left
And just for the record, Ring 1 would be the innermost ring that you can turn. Good luck.