How does Node Red work?

Question

Smart House

Let's say I have a smart home system that can turn on/off lights and receive messages from light switches. Those. I want to turn on the light when a button is pressed, I write some kind of condition inside the system code that sends a request to "turn on the light" if the message "button is pressed" is received.
Now I want to connect Node RED to this system. I am making an interface to the smart home system server, which allows you to receive and send commands to this server via a socket, for example.
What should I do next to tie NodeRed to this? Create my own node, which would implement communication with my server?