A few other thoughts.
I would, since you're unfamiliar with the grill, start with charcoal. Spend the first hour or adjusting the vents to see how she responds and get the temperature to the 200-10 zone. Make small adjustments to your intake vent on your firebox and wait 10 mins until the temp restabilizes to see the true effect. Otherwise you'll be rubber-banding up and down driving yourself nuts. When you think you have a handle on that, start feeding in sticks of wood, split to the size of you wrist, and see how that affects your temps and work to get it up to 225-250 and then put your meat on.
One option, since the grill is new, is to "season" it. So a search on "seasoning smoker" here and you'll find threads on it. The idea is that it coats the inside of your smoker and prepares it for food. Perhaps just as importantly, it gives you the opportunity to familiarize yourself with your equipment and learn how to regulate your temperature and get the right smoke which is what it's all about.
My main point is that if you don't have a handle on maintaining temps before you put your food on you're going to be anxious and could in fact ruin the food. Also, go sparingly with the wood when you start adding it. Generally, one stick at a time and let it burn down. It's mostly just for smoke and too much of it too quick and you'll have too much white smoke instead of the "thin blue smoke" you're looking for. To maintain heat you may find you need to add more charcoal later in the cook.
You're a lucky man to have a few apple trees to use. Don't burn it all up on your first cook :)