After logging into Amber X, tap Backup Now.
Select Auto Backup or Manual Backup.
Select Backup Device (could be an external USB connected to Amber X), Destination Folder, and whether or not to backup iCloud Photos.
To enable background backup:
Go to Settings > Backup & Upload > Background Service.
Run in the Background: Indefinite with enough power (recommended along with plugging in the charger)
Camera Roll Backup: Enable
Download & Upload: Enable
Note: Please be aware that there is a limit to how long an app can run in the background, whether iOS or Android. There is a strict limit by iOS to limit background activity by Apple with the exception of its Camera Roll/Photos app. iOS will close the app even if we enable it to run indefinitely and/or will be closed due to a large battery drain from excessive background activity.