Read help info
You can set your tablet to select a network automatically or you can select a network manually. If you select a network manually, your tablet will lose network connection when the selected network is out of reach.
1. Find "Carrier"
Press Mobile network.
2. Select network
If you want to select a network manually, press Choose automatically.
Press the required network.
3. Return to the home screen
Press the Home key to return to the home screen.