Download the dedicated server from steam, if you're talking steam version, edit your settings in the server.cfg file and your defined playlists in default.dspl (Which point to dsr's which you can also edit)
Then run "iw5mp_server.exe". Should be simple from there.
Heads up you'll need to enable port fowarding on specific ports. (Google can help you there)
Use the command
In the console (The box that pops up when you start iw5mp_server.exe) to start the server.Code:map_rotate