Find "Data roaming"
Slide two fingers down the display starting from the top edge of your phone.
Press the settings icon.
Press the settings icon.
Press More.
Press Mobile networks.
Press Data roaming.
Turn data roaming on or off
Press the indicator next to "Data roaming" to turn the function on or off.
If you turn on data roaming:
Press OK to confirm.
Press OK to confirm.
Return to the home screen
Press the home icon to return to the home screen.