Do you have the stones yet? If not, you need to find them. Use your first clue: "perhaps you should talk to other well-known figures". You'll know when you've found them, it's very obvious when you visit their pages. =)
If you have already found the stones, you click one, then click on the keyhole to place them. Once you've placed them all, hit submit, and if you got any of them right they will remain there. If some were in the wrong spot, they will be removed and you can try again after 30 minutes.