download that file and extract it. copy the files inside the folder to the UT2004 system folder on C:\ drive under the UT2004 file.
-Place all files in the \UT2004\System\ folder
-For single player, select 'Instant Action' and choose the ArenaMaster or TeamArenaMaster gametype. From within a match,
type 'menu3spn' into the console to bring up a full list of options and settings.