Where can I find a complete (easy to understand and use) tutorial or manual regarding the album JUPITER skin the explains how to use and apply file names, borders, folders, design variations?

And on each of the skin's setting panels, there's a link to the manual page for that panel. See screenshot.

But you don't learn a language by reading a dictionary. The best way to find out what the settings do is to create a little test project with maybe three folders, and a dozen images in each, and just experiment. Change a setting, make the album, preview the result, and so on.