How do I look at the files that have been backed up on my Passport? what format should they be in?
What type of files are you trying to open? What program did you use to create them?
If a Word document then it should open with word. If an image then it may open in Photos. What are your defaults for files? See example image below for setting or checking your defaults (Windows 10). Click on, tap or activate image to enlarge it.