Instructions
Move Harry (or the character playing) to one of the side walls with the D-pad or the touch screen. Stand by the wall for a couple of seconds. After the basilisk shoot the eye beams, move away from the wall. The basilisk will ram the wall. Pick up the item with the arrow over it out of the debris that the basilisk left when it rammed the wall. Place the item in the cauldron by the front of the room. While you move around the room, hit the basilisk with various spells.
Repeat step one until you place all three pieces into the cauldron. Mix the cauldron and take the potion.
Tap on the chain next to the gate on the left-hand side of the screen to open it. Fawks appears and will weaken the basilisk. You do not control Fawks.
Tap the chain on the left of the cylinder that Fawks came out from to attach it. Use your wand on the chain to the right of cylinder. The DS game computer will control the other player. Hold the stylus on the chain until the cylinder lowers.
Jump on top of the lowered cylinder. Run through the area to the Sorting Hat. Tap the Sorting Hat to reveal the Sword of Gryffindor. Tap the sword to kill the basilisk.