In order to back up your Virtual DJ library follow these steps:
In My DJ Cloud, go to the "Library Backups" menu, and make sure that Virtual DJ is selected.
Open Virtual DJ and click Browser Options (arrow #1 below)
Click Database, then Create Database Backup
Your backup will be created by Virtual DJ, and automatically be backed up in the cloud!
Since Virtual DJ backup creation is a manual process, you'll need to do these steps every time you want a new backup. Make sure to do it at least weekly!
You can view and download your backups from the My DJ Cloud app at any time.