Overview map of all the rooms. Use this as a reference for the rest of the guide.
Keys
Head to room 3. To get the first key. Backtrack to room 1 and open the door west.
Follow the red arrow path down and head to room 12.
Step Puzzle
The tiles flip from orange/blue and vice versa when stepped on. Make them all orange then pull the lever to open the path north. Head north to the next map.
Boss Room
Boss fight. Monsters have sandstorm. This is going to hurt if you don't have much AC or Cut Resistance. Loot the amulet from the boss and head north.