Instructions
Hold down the "C" button to make the spell wheel appear. Move the analog stick to highlight "Wingardium Leviosa," and then release the button to make that the active spell.
Press "Z" on the first piece of spear on the left side of the screen. Carry the piece to the broken spear in the middle of the room. Switch to your Lumos spell through the spell wheel.
Press "Z" at the Devil's Snare, a green plant, forcing it to let go of the piece of spear it was holding. Switch back to Leviosa and carry the piece of spear back to the middle of the room.
Navigate to the upper-left corner of the classroom. Arrange the blocks on the ground according to the diagram on the wall. When positioned properly, the blocks will form stairs you can climb to the upper level.
Switch back to your Lumos spell and walk up to the second floor. Immediately by the stairs, you will find another Devil's Snare. Press "Z" to make it drop the piece of spear, and use Leviosa to bring it back to the middle of the room.
Switch back to Lumos and return to the second floor. In the middle of the room is a vine holding another piece of spear. Press "Z" to drop the piece, and use Leviosa to return it to the middle of the first floor.
Return to the second floor, switching back to Lumos. Press "Z" on the Devil's Snare in the upper-right corner of the room, which will drop the final piece of spear. Switch to Leviosa and carry it to the first floor, completing the spear and the class.