Some users are having problems getting Time Machine to work in Sierra. Here are some suggestions to get that first backup completed.
When you keep documents in iCloud, are they backed up in Time Machine, searched in Spotlight, and kept securely?
When it rains, it always pours catfish. And most of the falling fish came courtesy of the App Store.
Should Time Machine back up on demand, or every hour? Sierra doesn’t seem sure. And how Apple needs to think of users more in the App Store.
Backups are no longer made every hour, but their frequency depends on the likely amount needing to be backed up. A hidden if not secret feature.
Are your backups made every hour? Are you sure? Sierra might have become smarter as to how often it backs up.
How often, and how much? Decide by thinking through how you would use your backup to restore your Mac after disaster.