If you can get it to run, the best way to play MUDs is using a MUD client. My favorite was always GMud because it could fit on a floppy disk with a world file,

If you can get it to run, the best way to play MUDs is using a MUD client. My favorite was always GMud because it could fit on a floppy disk with a world file, but ZMud was kind of the de-facto standard/best client, although paid. You can use a normal telnet client, but it needs to support ANSI colors and have a screen buffer to render most MUDs properly. Also, it depends on the MUD codebase they use, some of the older codebases are more friendly to very basic clients, newer codebases typically rely on using a telnet client like TinTin or a MUD client.