This plugin is a great idea. We have tried very hard to get the scheduled backups working but to no avail. In addition it is not possible to create a backup to anything but the Google Drive root folder.
All requests to this forum have met with no response from the developers so we can only assume that they've given up with their plugin and will not attempt to get it working properly. This is a real shame as it is so almost a great plugin, but the lack of scheduling and targeting of backups make it ultimately useless.