The key to Scholomance is called a Skeleton Key. It must be forged from the remains of a skeleton - several actually - and hardened by only the strongest of metals within a suitable mold. A signet of power from a being who naturally can open the portal to Scholomance will make the key ultimately function. First thing's first though, adventurer. We'll need skeletal fragments for the key's forging. Skeletons inside Andorhal should yield what we need, but the ones outside the walls might work too.