Question about managing backups of My Cloud

I’m running firmware v 2.31.183 on my My Cloud NAS and I have an external USD hard drive connected for manual backups of the NAS. I periodically connect the drive to the NAS, run the manual backup, and disconnect the drive. I store the drive in another location.

I have two questions regarding managing backups:

  1. Is it possible to change an existing backup, to add or remove folders that get backed up or must I delete the current backup job and create a new one?

  2. How can I check the backups to make sure they are good?

  3. Do the backups consist only of the files stored on the NAS or are the NAS settings backed up too?

Thanks in advance!