Have you already gone to the green spot on the map? and beat the ghost ship? If so, then after you drew the triforce, you should be in a room with a door that has the green symbol (except it's not green anymore =P) and you should be able to open it.I read that damn guide, but I'm still stuck after the blacksmith as I don't know where to write the triforce!
HOWEVER I went into the hometown temple and drew a triforce onto the red door and it opened (instead of an hourglass). But now I can't get anywhere in that dungeon :s I don't know where to go or if I am even on the right spot :s