1. Find "Wi-Fi"
Slide two fingers downwards starting from the top of the screen.
Press the settings icon.
Press Wi-Fi.
2. Turn automatic use of mobile data on or off
Press the menu icon.
Press Advanced.
Press the field next to "Auto-switch to mobile network" to turn the function on or off.
3. Return to the home screen
Press the Home key to return to the home screen.