I have everyone's answer. I couldn't find the answer in any forum at all so I came back to post the solution. I recommend starting with a fresh Catalina install, but I don't think it's necessary. Next, make sure you decrypt your hard drive. Then follow the normal process to install Big Sur Beta. I did the latest build. I am on a MacBook Pro mid 2015. Was running Catalina. The whole update took a few hours after download. Encrypt your hard drive again once you are running the new macOS. If you have any questions, let me know. ***EDIT: If you screwed up your system, no worries. Make sure you are connected to the internet and run Command P to install a fresh copy of the original OS your Mac had. Then once you have a fresh install, follow the normal steps to do the beta install. I had previously tried all the refresh of PRAM etc etc. This is the only thing that works.