For information about backing up manually now, see Back up your iOS device to iCloud. If you don’t see a backup you expected to be there, see the Apple Support article iCloud: Troubleshooting restoring an iCloud backup.
Go to Settings > General > Reset, then tap “Erase all content and settings.”
In the Setup Assistant, proceed to “Set up your device,” tap Restore from a Backup, then sign in to iCloud.
Proceed to “Choose backup,” then choose from a list of available backups in iCloud.