Hello there,
Please read the rules:
http://www.oddworldforums.net/showthread.php?t=11928
I am not familiar with Dungeons and Dragons, and what is a DM?
Anyways, it's not like it at all, i can see.
Well, the RPGs here, are based on Text, it's like a story where evrybody can write on it, using their own characters. It's like when you play with someone actually, just on Forums. Youcreate a character for an RPG and start posting in it.
You can interact with evrybody. It's a bit difficult to explain.
If you're in doubt, please check out the Work At Rupture-Farms RPG, it shows how it's done:
http://www.oddworldforums.net/showthread.php?t=10647