Connecting to a Server

Hi, I want to learn about the Client class for processing because I want to build a console to communicate with other people, the problem is that I do not have a server that I can use. Online I found that you can technically use your PC as a server but I couldn’t understand how (I use macOS 11.1) and most importantly I couldn’t understand how to use the Client class if the server is the PC that the program is running on. DOes anyone know how to move from here?
Thanks :slight_smile: