Search the chest in this room to obtain the first map piece. Kill the lesser demon (level 79) and use the black key it drops on the northern door leading to a small room with the wooden floors.
Follow the passageway and then go down a series of ladders to reach the basement.
Good food, full prayer points, and potions are all good items to bring if you have them. Use of Silverlight may help low-level players defeat this high-leveled monster. Head to a bank in Falador and stock up for combat against several monsters including a level 79 lesser demon. When you're done, he will give you the Maze key to get the first map piece.