First you have a v2.x My Cloud. WD changed the terminology when they changed the firmware between the older generation v4.x My Cloud units and the newer generation v2.x My Cloud units. They are two different units that use the same name. Under the v2.x one uses Backup to copy the contents of the My Cloud to another location/device.
Second, there are several past discussions on the lack of a scheduling feature/option with the v2.x Backup feature. One can find those past discussions using the forum search option, the magnifying glass icon upper right.
Feel free to voice your displeasure at the crippling of the Backup feature with its lack of a scheduling option in the following Cloud Ideas discussions.
https://community.wd.com/t/schedule-queue-usb-backups/96993
https://community.wd.com/t/request-for-scheduled-usb-backups-from-nas-to-usb/150539
