1. Open G Cloud App.
  2. Tap the Menu icon  in the upper left corner of the app.
  3. Open Settings.
  4. Tap the Automatic Backup option.
  5. Set Upload files to G Cloud When Charging. To add more specific settings, tab on Customize.

By default, G Cloud will run the backup while charging your phone and when it is connected to WiFi.

 You can also set the phone to backup at any specific time you wish. (Learn more)