The Home screen normally has two tabs (three if your meter is in prepayment mode).

When your Trio is powered on, it will automatically show the Home screen once connected to the smart meter(s).

                Touchbutton home screen                                           Touchscreen home screen            

For Touchbutton: 

You can at any time, press the Home button to return to the Home screen. When you next return to the Home screen from other screens, the previously selected tab will automatically be shown.

For Touchscreen:

For the Touch screen, touch the tab you want to switch to.