1. Find "Enable 4G"
Press Mobile Data.
Press Mobile Data Options.
Press Enable 4G.
2. Select network mode
To turn off use of 4G, press Off.
To use 4G for both voice calls and mobile data, press Voice & Data.
To use 4G for mobile data only, press Data Only.
3. Return to the home screen
Slide your finger upwards starting from the bottom of the screen to return to the home screen.