Congratulations on fishing your first tournament!
Possum Kingdom will be an exciting lake for your first time out.
These are some things we advise our team to do in preparation for tournaments:
Not sure which school you are at, but in case your campus advisor was not able to get a copy of the rules in your hands, so please find them here http://www.texashighschoolbassassn.com/
under the blue bar that says "2016-2017 THSBA Tournament Rules." You can tell by the boys response above that not everyone reads the Tournament rules, and apparently they have been burned.
On that same page you will want to click the red West Division Page and review the Possum Kingdom Information for rules specific to this tournament.
As for fishing tips, you can find lots of Possum Kingdom videos on YouTube that will give you an idea of the structure and cover you will find on the lake. Honey Hole has one from just a few weeks ago. You can also do a search for early fall fishing in North Texas for more tips.
Mike Iaconelli's facebook page has had some good information on it recently. He has some good videos at bassu.tv too.
You can look at Google Maps to see what may be decent locations. Keep in mind that the lake has a lot more water in it than it did in those images. You can scope out all those bridges that have been referenced. I would recommend that you pick up a map of PK if you can find one. You can also order all the Texas lakes online. We got all of them from http://lureoftheoutdoors.com/texaslakemaps.aspx
These are good to have, especially if you don't have a GPS or it goes out on you.
Be sure to check the weekly fishing report on the Texas Parks and Wildlife page, and also pay attention to the weather. It is going to be COLD Saturday morning.
Also, if your boat captain is an experienced angler, ask him/her for recommendations for bait and line.
PK may be a tough lake with such a weather change coming between now and Saturday. Don't be hard on yourself if you don't weigh anything in. With a 16-inch minimum, there will be a lot of teams that don't. Even if you don't catch anything, TURN IN YOUR FLIGHT CARD. It is still possible to make regional tournament cut, but you will NOT if you don't turn in your cards at weigh-in.