Open the project with Unity Editor. The '/lonely-tetris' folder is the project root project.
Switch to the "Main" scene in Unity Editor by double clicking on the "Main" scene under the /Scenes folder in the "Project" view.
Run an instance of the application in windowed mode. From the Unity Editor select: (File -> Build & Run -> Build & Run).
Run a debuggable instance of the application in the Unity Editor by clicking the Play arrow.
In one of the application instances choose the "LAN Host(H)" option. This application will run the authoritative server, and a client.
In the other application instance choose the "LAN Client(C)" option. This application will run a client.
Use WASD to control the game.