This is a quick howto for self-hosting SyncLounge, a useful tool for hosting watch parties for your Plex server.
If you just want to host a plex party, you can use the public synclounge.tv server. If you want to use Docker instead of mucking about with Node, the SyncLounge readme describes it. This is for running the NodeJS yourself.
You don't need programming experience to set SyncLounge up, but without a passable experience configuring linux, you're probably better off using synclounge.tv instead.