As fancy chatrooms, MUSHes are best played with a little bit of support software. Your easiest option is to use this browser-based client.
If you've had a look around and think you'll be sticking around, there are a number of downloadable client programs, such as MUSHClient (Windows), SimpleMU* (Windows), Pueblo (Windows), Savitar (Mac), or TinyFugue (UNIX, Mac, Windows). (Not an exhaustive list.)
Failing that, you can telnet in to the game via any standard telnet program, with URL darkmetal2039.com and port 2039. This is not a recommended option, as telnet is a very raw and user-unfriendly medium.