If you have install uniCenta by default setting, you will be using apache derby database.
You can find the database location by going into Configuration section of uniCenta as the screenshot shown below.
(Click on the imgae to enlarge)
This is the folder you should backup.
Let’s open up file explorer go to the folder.
From here you can simply copy and paste the folder to create multiple copies. You can also using ZIP / RAR archive program to make backups.