Here some people dunno what exactly to do inside so i made this quick and simple guide on how to run it.

first here is a simple blueprint of DX dungeon (dun laught at it, thats epic paint skills mang XD)

After you enter the dungeon You will see a mob right away, kill that mob and click the stone to the right side to progress thru the quest.

go on and you will get to the main platform, there is a stone in front, click it and mobs will appear right on the platform, kill the mobs until the gate on platform "B" opens up

Once the gate opens up, go to platform "B" and kill the mobs there, i am not certain which specific mob u have to kill to be able to access the stone to progress thru the quest, but thru my runs i think its one of the "male" zombie resident. keep killing mob and try to access the stone, once u can access it, progress thru the quest and go back to main platform, there will be new mobs that would spawn, kill this mobs until the gate to platform "D" opens up

once its opened up, go to platform "D" and kill the mobs there, (this time i think its one of the "femal" zombie resident that u gotta kill) once u killed the right mob and able to access the stone to go thru the quest, you will be able to attack the gate of platform "C" 

once u opened it up, kill the mob named "Disappeared Jewelia" and it will drop "jewelia's necklace", Pick it up, talk to the stone on the platform (D) and the gate to the platform "A" is opened up where the first boss lies.

once done w/ the boss click the stone on the platform(A) and its time to go thru the quest.

this is the specific mobs to kill for the final boss to spawn

Platform "D"

Swordsmen Ghost

Platform "C"

Archer Ghost

Platform "B"

Fighter Ghost

Once you killed all the specific mobs on each platforms a "warning" sign should flash and the Final Boss of the dungeon should appear on the "Main Platform"

(Note: this boss teleports after a certain period of time, so for FA/FS that would use AoD+MB or AoS, better use it quickly =P)

Once your done killing the last boss it would drop a stone, pick it up, Open up the Chest on the "Main Platform" and then go back to the starting point and finish the dungeon thru the stone there 

And thats the rap on this quick guide to DX Dungeon : Catacomb Frost.