Samsung Galaxy A5 (2016)
Android 5.1.1
1 Find "Search networks"
Slide your finger downwards starting from the top of the screen.
Press the settings icon.
Press Mobile networks.
Press Network operators.
Press Search networks and your phone will search for networks.
2 Select network
If you want to select a network automatically, press Select automatically.
If you want to select a network manually, press the required network.
3 Return to the home screen
Press the Home key to return to the home screen.