If people are having trouble understanding the new multiplayer system just @ them over here.
First read this: Object Picking - GDevelop documentation
Object picking is crucial when trying to understand this code.
This is the games link: https://games.gdevelop-app.com/game-5d52e21c-e44e-46cd-a596-f0abce5ab954/index.html
And here are the images.
This is the Lobby scene code:
Then this is the Game scene code:
This image is only here to fully show Restart