The manual for that flash is basically a one-page document. I can scan it and email it to you if you like (give me a day or so). PM me if interested.
If you have a basic understanding of the relationship between aperture and ISO, and the relationship between aperture and distance, it will all click in your brain when you move the sliders on the unit. If you get stuck, feel free to ask.
The ability to change ISO with a digital camera makes these things more versatile. For instance, you can set the flash to f/2 & ISO 100. That same setting will work for f/2.8 & ISO 200, f/4 & ISO 400, etc.
Have fun!