I could give you a very general "flash photography basics" answer, but I am sure that much you already know. Unfortunately, what would be most helpful is a manual, and the only place (www.craigcamera.com) I could find one wants $18(!!!) for it - I have failed in finding a freebie. I know that my Sunpak has a manual (M) and auto (A) setting, as well as a dial scale for setting power. The rest of the scale should tell you how much power to dial in for the f-stop you are using within a distance range from the subject. As to how to use the auto settings, I don't know that. Perhaps someone has a manual or experience with this flash? Good luck,