After you've installed Soft Serve, you can `ssh your-user@mash.example.com -p 2222` with the ssh key you defined in `soft_serve_initial_admin_key` to see TUI and follow the instructions to configure Soft Serve further.
Note that you have to [finish the configuration yourself](https://github.com/charmbracelet/soft-serve#configuration), otherwise any user with `soft_serve_initial_admin_key` will work as admin.