Right, it’s called a signaling server, which is mainly what PeerJS seems to be. You need a method of connecting peers through the signaling server, they decided

Right, it’s called a signaling server, which is mainly what PeerJS seems to be. You need a method of connecting peers through the signaling server, they decided on generating uuids that are shared out of band or through a peer discovery api. You can do this pretty much however you want, the spec doesn’t clarify at all by design.