As others said, leave your phone at home. If you mask, STAY masked. Don’t do anything you don’t feel comfortable doing, especially since you don’t know anyone yet. You’re always free to dip when you are not feeling comfortable.

Don’t worry about approaching anyone to state your intentions. If you want to make yourself known, you can approach someone and say you’re new and there to support and want to know if there’s anything you can do to help the demo. Otherwise, just hang out in the crowd and try not to stick out.