Simple project to work on a host/client basis

Hello, I've created a simple boardgame in Unity and wanted to add very basic LAN & online multiplayer - but I don't know where to start. Basically, I want to make a system where one player acts as the server and other players join a game on their machine. All I need to do is be able to send simple updates to an array and other similar information across to the other players. Physics isn't at all important. The game currently only supports AI players, or players using the same machine.

What would be the most practical way to do this?