The ability to restore Paper 2 and Paper 3 content into Paper 5 from backup is no longer available.
The Backup service available in Paper 2 and Paper 3 was shut down Tuesday March 27, 2018 at 11 AM EDT. Access to restore the backups was removed in Paper 4.3 released on February 28, 2019.
Please feel free to open a support ticket if you have any questions.