1. Turn on your device
2. Wait for it to fully power on Sometimes this may take a while
3. Make sure you have the most recent version of iTunes
4. Connect the device to your computer.
5. Most of the time iTunes will automatically start up, if not start iTunes.
6. Ensure that "Find my iPhone is turned off (Settings -> iCloud -> Find My iPhone)
7. If you are using Windows, click on Start, and type %appdata% and press enter
8. Copy the folder "Apple Computer" from the provided USB thumbstick to the new window, this copy may take quite some time.
9. In iTunes, select your device from the menu:
Restoring your device with the provided backup.
10. Click "Restore iPhone"
11. Your backup should be available, choose the backup you wish to use
12. Click Restore
13. Wait for the Restore process to complete, and your device to restart and sync again with your computer. Congratulations!