Run the file. The port is on the last line (no. 13) so you can change that.
In another terminal, on the local network or on the same computer, type nc <local IP of server (or localhost)> <port (default 9000>. Then, you can type stuff to send it, and type /nick <nickname> to set your nickname. You can connect with as many terminals as you want. You can also port-forward that port to be able to access the chat room outside of the local network.
Great!