Just be early.

If you’re leading a meeting that starts at 9, get there with twice as much time as you think you’ll need to prepare.

You’ll get lost, the tech will fail, they’ll change your room, the tech will fail, someone will knock over an urn of coffee in the corner, the tech will definitely fail.

It’s better to be there early with time to spare to greet the people coming in,than to be scrambling while they mill around, unwelcomed.