The are two options.
1. If there is a keyboard connected to the pc press alt+c to switch to the configurator.
2. If there's no keyboard you can use your touchscreen; keep your finger pressed on either the lower left or upper right corner for 10 seconds until a popup appears. Enter the password using the pop-up keyboard (the default password is "asdf") and press continue. From here you can select to close Omnitapps4, shutdown the system, switch to the configurator or minimize the application.