Samsung Galaxy A51 5G
Android 10.0
1 Find "Network operators"
Slide two fingers downwards starting from the top of the screen.
Press the settings icon.
Press Connections.
Press Mobile networks.
Press Network operators.
2 Select network manually
Press the indicator next to "Select automatically" to turn off the function and wait while your phone searches for networks.
Press the required network.
3 Select network automatically
Press the indicator next to "Select automatically".
4 Return to the home screen
Press the Home key to return to the home screen.