She'll have to paint/align the 3 paintings in the room, starting bottom up. Once they're all aligned, the spirits will open the doors.
In the middle of the room, there's a raised gear with 3 gears surrounding it, one of which is not thinnable. Using the raised gear will raise or lower the floor. With the two surrounding gears thinned, it takes you to the bottom floor. 1 painted, 1 thinned, middle floor, and both painted, upper floor. After painting or thinning the side gears, spin the main one for the change to take place.
Each of the 3 paintings is composed of 3 pieces, one piece per floor. Spin next to the desired painting to shift it to the side to get the matching piece. You may have to paint some pieces in. Spinning next to a painting piece causes the pieces above it to also spin, so working bottom up is the best method to go.
If for whatever reason you need to reset the floor, thin one painting wall and walk through it. In there, spin the central gear until you see a hidden gear. Spinning that will lower the floor to the first level. Careful, the floors behind the painting are thinnable!
Good luck!