Welp, you need to go to
http://www.skulltag.com/
Then go to downloads
Then download the windows installer it will down load the .exe installer, after it installs it will ask you to locate the folder with the .wads. Ill shoot you a PM and inform you about the wad files, which is the doom game its self.
Then you need
http://doomseeker.drdteam.org/
From there go into the downloads and download the 0.7 beta, once its installed it will ask where skullktag is, it needs the folder with the skulltag.exe, cause it will start skull tag when you join a server.
After that, start doomseeker, go into options -> configure -> engines -> skulltag. There is a master server address and you need to change it to
master.skulltag.net:15300
Once thats done, all youll have to do is some gfx tweeks once skulltag loads and your in a server, it can use open GL which looks 1000x better then vga but more cps dependant. And then some key mapping and your done.