From what I've read, what you need to do is count the number of rocks in the room your in. Then depending on that, go in the clock position the number of rocks indicate. (E.g.: 3 Rocks: Go through the entrance at 3:00, go through the entranceway at 6:00 when the room has 6 rocks, etc.)
If you follow the "clock positions" the rocks indicate, you will be able to find Selphy. Going in the opposite direction indicated by the rocks will lead to an item.
Source
I hope I helped!