[Sh4d0w2]

Go into SA-MP Server folder, open server.cfg and there's a gamemode line, add the gamemodes name in there and remember that it has to be a .amx file, so if you have made your own script then compile it and the .amx will be automaticly produced. Oh and just to help you out if you didn't know the Gamemodes are located in the Gamemodes folder