How to properly stop a game ?

I am browsing all the functions fo the NetworkManager and Matchmaker, but i dont see a clear answer there.

Basically, i have got my matchmaker setup, 2 player sjoin the game, fight, and eventually one of them looses.
That's where i am stuck...
For the context : I am not changing scene. I have only a MainScene , players connect together via matchmaker, spawn the level prefab, play, .. and...i am stuck.

So i am not sure what i should call and in which order ...

Any help please ?