Seasoning means taking the shining/mirror like finish off the interior walls.Think of your grandmother's old cast iron skillet.The more years she cooks in it,the darker it gets.If you have no wood,look around on the ground and pick up a few pieces of hardwood or fruit wood.
If you have the wood you will cook with on Sunday-that is "the perfect" wood.
Either of the posts above will work.If you don't have time to get to town and shop,look around your freezer.Anything fatty that has been in there too long.Frozen groundbeef,old package of bacon,old pack of fatty spares been there until funny colored.
Toss something in there and let it run for four,or more hrs.
Fast Eddy used to tell us put about 2 lbs/ 8 hamburgers in and slow cook them. Unseasoned won't hurt your product,but seasoning lets the cooker run a little more evenly.
Over the years we have started saying"porkbutt",because you can eat it.
Enjoy.