Fill Flash Assignment

So for photojournalism class we are having to do an assignment dealing with fill flash. Basically fill flash is "filling a space" with a flash on top of your camera. I have already pretty much decided that I want to get the SB 900 Nikon flash but I have to get it before I do this assignment, which put a short time frame on the delivery of the flash. So basically right now I am FREAKING out about getting the flash in time. But I am also excited about this assignment because it will teach me how to use a flash which I have been needing to learn. Basically fill flash will do this for your image which is a great difference.