Startup arguments can be added in the ns_startup_args_dedi.txt file.\
Example: +setplaylist private_match +mp_gamemode ps
Arguments
Accepted Values
Description
+setplaylist
see Gamemodes (Should be the same as mp_gamemode unless you want a private match)
Set the server type (If it is not private_match, make sure you have also included +map and NOT mp_lobby or else you can't search your server in the game)