Zelda : Phantom Hourgl Help.?

The third time you go into the Sea King's temple (when you have 12:00 minutes in the hourgl) how do you press what do you do to open the final door? Celia (the white fairy (the pointer)) says that I have to press a certain map or chart against the door. Can you tell me exactly what to do? I don't even know how to press it against the door!