1) Download plugin .jar and put it in your plugins folder.
2) Start the server and open config.yml, specify which type of storage you will use (If you set MySQL, don't forget to put all the data in the MySQL section)
3) Customize all messages, command prefixes, ban command and permissions that players that are not in the whitelist get banned. (Specify if players with op also get banned!)
4) Reload the server and give whitelist to the players that you trust with the commands that you specified in config.yml
5) And there you go! You have setup an additional protection system for your minecraft server!