In this level you have to take the junk you find in the chest of junk and place it into the sockets later in the level. If you open all the chests and hit all the switches along the way to the end, you'll be okay. Grab the Junk, Crimson Red Key, and you will be fine. I'd recommend exploring the level as much as you can though, for the experience and items.
Note: If you ever see a marking on the wall that says, "This is the dwarven rune for safe passage," then you are near a false wall. The false wall is on the same wall as the rune.
The enemies in this level include skeletons, zombies, and frogmen. Some frogmen can cast spells, but in general they are weak. The bosses in this level can be tricky. The first boss can't be hurt by magic spells, so concentrate on killing his helpers. Using Turn Undead repeatedly could eliminate many of the enemies you'll face. The second boss can be hit by magic and has less helpers, so he can actually be easier.