Hi Pritch,
Open a browser page on your phone/tablet and type in the IP address shown on the B2 (both need to be connected to the same WiFi network).
Actually you are using the Web UI but on a mobile device, such as a phone, you will have a limited display and can chose what to display - the default screen on my iPhone is 'Now Playing' with options to play/pause, skip tracks and volume control.
Paul
Brennan Support.