Understand
https://www.html5rocks.com/en/tutorials/webrtc/basics/
Opinions for game
Opinion against https://www.reddit.com/r/gamedev/comments/cgvqr5/anyone_use_webrtc_for_a_multiplayer_browser_game/
General demo
https://www.youtube.com/watch?v=Dx-_wnLuMpU
Native webrtc
Example of multiplayer game using pure WebRTC