Bukkit

New selection system
In this version its possible to manage multiple cubes. Thats why you need to select the deathcubes you are working with. You need no selection if you have only one cube or if you have set a default cube. Otherwise and always for creation you need to specify a cube by typing /dc select <name>.

Cube creation
To create a cube you need to select your new cube first. If the selected cube does not exist, the plugin will the tell you that you should set the first position to create it.
I. Type /dc select anyName
Now you need to select the location for the cube area. Use /dc pos 1|2 to mark the edges.
II. Go to one corner, type /dc pos 1
III. Go to the opposite corner, type /dc pos 2
Now you would be able to create the cube, but you need to set a spawn before players can use it.
IIV. Find a cool place and type /dc spawn
Okay you could play now but surely you want to change the blocks, so search a place for the blockbar.
V. Use /dc bar to spawn the blockbar along your facing direction

Blockbar
You change the blocks of your cube by changing the blocks in your blockbar. The upper row represents the cube, the lower one the cage. The glass block marks the origin and is not important but on top of the glass you can define the floor of the stage where players are spawning in. After changing the blockbar you need to run /dc b r (or /dc bar reload) to let the plugin reload the blocks. It will stop reading blocks when it detects any air block or it reached 20 blocks. Also the blockbar is protected from break/place events by non-moderators.

Classic
If you want to play without any limits (no burning) just set timeLimit to zero and burnLimit to zero or above the height.

For the rest just read the command page.