What is the yellow button for and how do I use this?

1. This is a programmable button with a number of options
2. Go to the settings menu, scroll down to “Programmable Key” and select
3. This will open a selection that you can choose your favourite from for example Camera. You may select two, one for short press of the button and one for long press
4. Then select ‘OK’
5. When you return to the home screen now when you long press on the programmable button the device will go to your selected view