Huawei nova 5T
Selecting network
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.
Press Settings.
Press Mobile network.
Press Mobile data.
Press Network provider below the required SIM.
Press the indicator next to "Automatic" to turn off the function.
Press OK and your phone will search for networks.
Press the required network.
Press the indicator next to "Automatic" to turn on the function.
Press the Home key to return to the home screen.