The solution is not obvious but you'll notice that each stone has 2 symbols on it. One on
the floor tile in front of each stone and the other on the stone itself. The one on the
stone tells you the correct symbol that must be "placed" there. The one on the floor
indicates the one you are "placing" when you touch it.

So when you "touch" stone the symbol on the floor tile will be the one you need to place.
So look for the correct matching symbol and activate that stone next.

I realize that by reading this you might still wonder wth i mean, but it should make sense
to you soon enough.