O.k. well first you need to figure out how u are going to topic this article. Is it going to be like a run-down of the sport in general, or are you going to pick a game and give a play-by-play speech about it. If the first one, go to a simple website that lists all the rules. There are alot so you should be able to find enough to write 500 words(Its not as much as it sounds).You could even go more in depth about it and explain some instances or give your thoughts about if they should be changed. If you are going to do the second one, try to look up or remember a close game, and simply type what's happening. If you do that you might have to even shorten it because the words will add up faster than you think. If your teacher rewards creativity, make up your own game with fake teams and a fun ending. You could even put in some quotes from your pretend all-star.