Simply put, you can’t. Unless you set it up, the drive won’t be backupped anywhere.
If you want to have it backed up to the cloud, there’s this extension app called Crowdstorage, which offers weekly backups up to 1 TB for free.
If you want to have the backup with you (on a secondary HDD, for example), you can set up a computer to automatically backup the My Cloud Home using a program like Cobian backup.
