To log into rcon (remote control) to your PZ server you must go to the folder "rcon" located in your PZ installation directory on your PC and run the rcon-gui.bat file.
A window will open, then you need fill in the fields as follows:
address: the IP address of your server
Port: The port your server
password: rcon password for your server
To change the rcon password of your server go to your control panel and click "config files" and edit the file "server.ini". Change the rcon password (rconpassword), save and restart your server.
Once connected to rcon you should see the message "[RCON] Connected". You can then use admin commands without having to be in-game.