Any tutorial for local multiplayer

Hi folks, I would like to create a multiplayer scene (one room) and allow access to only 10 users (10 characteres) from a private group. I am not a programmer and don’t know what requirements are to make something like that.
I think each user should install the executable on their computer, but how is the information synchronized between computers?
Is that the method? or is there another?
This is not a scene for hundreds or thousands of players. It’s only for 10 users (or less) at same time.

Pixel Streaming is not a valid option, because it requires the use of a Tesla or Quadro card to have multiple cameras in the server. (It is better each user runs the game on their computer).

I wouldn’t like to use host like amazon, gamelift… to host the game.
The main idea is to use the executable in each computers and synchronize information by any server (a computer with open ip for example).