Can anyone let me know if the BR800 is compatible with audacity and how I would set this up?
If you mean the Boss BR-800, then it is a stand-alone recorder, so you don’t need to set it up with Audacity - it’s designed to work on its own.
Yes it is a stand alone unit but it can be connected to a desktop system and mastered then saved or burned to cd
If you have a reason to use it as an audio interface you must connect it to the computer, then when Windows sees it in Windows Sound, launch Audacity and select the BOSS USB device in Device Toolbar as playback and/or recording device depending what you want to do.
Using the computer to record from BOSS is potentially more error prone than recording direct to the BOSS. Also you probably won’t be able to record more than two simultaneous channels if you use Audacity as the recording application.