What do I do?
 

I downloaded the doom III alpha, how do I start the game. It's all extracted. In the Doom_III folder there is a doom.exe that I clicked on and it just plays a video. There is a folder called base in the Doom_III folder, how do I play the game?

http://www.megagames.com/news/html/d...miiileakeddemo!.shtml