Boy I hope you're all ready for this beatsaber lobby in 2 hours. I'm all healed up now and ret2go.

Beatsaber has updated since the last time we played so before joining make sure to run the game once then run mod assistant and update all core mods + custom avatars. Finally, download the multiplayer mod below and install manually. 
https://github.com/superrob/BeatSaberMultiplayer/releases
You'll just need to merge the folders over into whatever directory beatsaber is installed to then run IPA.exe.

If you a linkless quest user I can't help you.