How do you set up the box with no screen or keyboard?

No monitor, no keyboard, no router settings.

1. Plug it into power and into your router.
2. On your phone, open baumeister.host/setup.
3. Press the power button on the box once.

The button press is the point: claiming a server takes physical access to it. Then you set your password and add an authenticator app, and you're in.