You can find this information in the DXD manual located in the DXD folder under Marketing Documents.
Or you can download the latest DXD manual from this link. http://dxdxray.com/?wpdmdl=3

On the Menu, Utilities, there is Data Back-up and Data Restore options.
It is advised that you periodically backup the data to an external drive so you will not loose data in the event of a hard drive crash.

Select Data Back-up to back up data.

Select Data Restore to Restore from a saved backup