Press the five tiles in the following order:

Back wall
1. Middle tile
2. Left tile
3. Right tile

Side walls
4. Left wall tile
5. Right wall tile

This will give you the blue stone, which goes into the hexagonal spot in the ceiling. Light will show the order of the symbols on the stone ring below:

Outer ring: Cow head
Middle ring: Jar
Inner ring: Leaf

Remove the blue stone from the ceiling and place in into the center of the stone rings.