If you choose the option to quarantine files detected by cPGuard, files will be moved to the quarantine directory. Even though it is easy to track the quarantined file [ we use a special naming convention for easy identification ], you cannot really copy the file from quarantined location to actual file location. Rather you can follow the below steps

Go to WHM >> Plugins >> cPGuard >>  Virus Scanner >> Scanner Logs >> Locate you file which you need to restore and click on the "Three Dots Icon" in the right side of the row. It will pop-up  a new menu and Select "Restore File" from it.