Restoring to the SAME device after an uninstall or factory data reset:
Because the backup is stored on your SD card or media directory, it will not be erased if the app is uninstalled or a factory data reset is performed. To recover your data, reinstall the app. When the the opening screen appears (which asks what type of account you would like to sync with), choose the option to restore from the backup.
Restoring to a NEW device:
If your device is replaced or upgraded, you will first need to copy the backup from your old device to the new one. If both the old and new device have a SD card slot, one option is to simply move the SD card from your old device and place it in your new one.
If either your old or new device does not have a removable SD card, you will need to use your desktop PC to transfer the files. Plug your old device into your PC and then copy the folder named "Ultimate To-Do List" or "Ultimate To-Do List - Tablet" onto your PC. Then, plug in your new device and copy this folder into the top level folder on it.
On your new device, disconnect from the PC and install the app. When the the opening screen appears (which asks what type of account you would like to sync with), choose the option to restore from the backup. If you don't see this option, either the "Ultimate To-Do List" folder was not copied to the correct location, or your device is still connected to your PC (which sometimes blocks access to the SD card or media folder).