Well, i guess you are going to create it on Windows, so:
1.Open notepad
2.Type in: paintball2.exe +set dedicated 1 +set public 1 +exec server.cfg
3.Save as server.cmd in paintball directory
4.Create server.cfg in configs directory (if doesn't exist)
5.Set it up using documentation:
http://digitalpaint.org/docs.html6.Run server.cmd
Not easy, but after some tries it might work ^.^ .