1 Find "Network mode"
Slide your finger down the display starting from the top edge of your phone.
Press the settings icon.
Press the settings icon.
Press Networks.
Press Tethering & networks.
Press Mobile networks.
Press Network mode.
2 Select network mode
Press GSM / WCDMA / LTE auto, GSM / WCDMA auto, WCDMA only or GSM only.
3 Return to the home screen
Press the home icon to return to the home screen.