Installing Half-Life:Decay to PC

Decay was originally a PlayStation 2 -only version until a port to Windows was created by a second party. The original game design is inherently multiplayer, so in singleplayer mode the port runs the other character as a bot. The instructions say the game has to be booted as a LAN game, which I have no experience with. I downloaded and installed the port but can’t get it to run; the installed folder contains no .exe file, so presumably it’s run through one’s original copy of Half-Life . I think either I have to somewhere somehow tell the game what “server” to run from, or else the versions aren’t compatable; can someone who has succeeded in installing this tell me how?