You have posted to the Movie Edit Pro area of the forum but your question is about Photo Manager so I have moved your post to the Photo Manager area.
Which exact version of Photo Manager Deluxe do you have? The standard route for accessing the Help files is via the Help>Content menu listing. Have you tried that?
The current version of Photo Manager Deluxe is 13.1.1.12; at the moment I can find no source for any manual to actually download, rather than access via the program.
If you have an earlier version of the program, this page will allow you to download the manuals for version 10, MX and 12.