This article relies on the live media created here
From a readable disk
Open the File Manager from the applications menu, you should see your disk in the pane on the left. In the below image, it is the “11GB Volume”
Double click the desired disk and it should open in the file manager.
Once opened, you can drag and drop files to another disk that you mount into the system just like in Windows.
Testdisk to recover partitions or a partition table
Using Testdisk to recover partition tables