It says: "To enable Droplet backups on an existing Droplet, from the control panel, select Droplets and click the Droplet you want to enable daily backups on. Then, click Backups in the left navigation. If the Droplet already has weekly backups enabled, click the Edit Settings button. If the Droplet does not already have backups enabled, click the Setup automated backups button."
There is no Backups menu item for a selected droplet!