Instructions
Use the "Leviosa" spell and fly across the Mermiad lair on your broom to get past the "Black Lake" level. After a short video interlude, the characters will go back to Hogwart's Castle.
Climb up to the first painting on the wall. Talk to the painting, listen to his message, and wait until the first two flights of stairs move toward you.
Run up the first flight of stairs and stop at the edge as the second flight of stairs approaches. If you fall off, talk to the painting again to reset the stairs and start over.
Use your wand to cast the "Reflecto" spell and blast the large box on the top of the second staircase. In the box is a LEGO steering wheel. Pick up the steering wheel and carry it over to the wall.
Hand the steering wheel to the painting. Use the lightning wand spell to make the steering wheel rotate and move the next two staircases.
Battle the pixies as you run up the next two staircases. Use the wand for far away attacks so you are not knocked off of the staircase.
Pick up the painting on the balcony floor and hang the painting on the wall. Use the wand to zap the painting. It will come to life and the last staircases will connect.
Climb up the last sets of stairs until you reach Dumbledore's main office. Enter the office to complete the staircase puzzle.