You can set your mobile phone to find a network automatically or you can choose a network manually. If you select a network manually, the network connection will be lost if you're out of range of the selected network.
Step 1 of 9
Find "Network operators"
Slide two fingers downwards starting from the top the screen.
Step 2 of 9
Find "Network operators"
Tap the settings icon.
Step 3 of 9
Find "Network operators"
Tap More.
Step 4 of 9
Find "Network operators"
Tap Mobile networks.
Step 5 of 9
Find "Network operators"
Tap Network operators and wait while your mobile phone searches for networks.