Read help info
You can set your phone to select a network automatically or you can select a network manually. If you select a network manually, your phone will lose network connection when the selected network is out of reach.
1. Find "Network selection"
Press the Navigation key.
Select Phone settings.
Select Network selection.
2. Select network
If you want to select a network automatically, select Automatic.
If you want to select a network manually, select Manual and wait while your phone searches for networks.
Select the required network.
3. Return to the home screen
Press the Home key to return to the home screen.