Can't Retrieve Backed Up Files

I’m trying to use a My Book external HD which has not been used for many months.
I erased everything on it, downloaded the HD software, and did the back up from my Dell XPS W 10 computer.
The My Book has 516 GB of data on it now. It was empty before the back up and has a file on it named WDBackup.swstor
Now I’m trying to test it to Restore a file.
I clicked on Restore. The window “Files to Restore” comes up but nothing appears in the window Restore Files.
It is almost as if it doesn’t read the back up drive.
Any ideas where I go from here?

I think you have to use the WD software that used to back up the data to restore data. Not Windows “Files to Restore” to restore your data. From the look of the file “WDbackup.swstor”, it looks like you using WD software to backup your data.