This area will only show up once you've accepted the bow mastery quest.
1 - Bowmaster Dungeon Key #1
2 - Bowmaster Dungeon Key #2
3 - Torch
When you shoot the torch with your bow (go into combat mode and then alt-click on the torch) you'll be teleported to level 2.
4 - Starting Point in Level 2
The entire level is a long gauntlet where you'll have to shoot (or run past) tattered bowmen hiding behind rocks.
5 - Torch
When you shoot this torch you'll be teleported to the treasure room.
6 - Treasure Room
The Bow of Ecclesiastes is in the chest. That's the bow Kietzel Pierce wants. When you shoot the rightmost torch near the chest you'll be teleported out of the ruins.
A. Exit back to the world map.