Welllll..... Its not that straightforward. But, its not that complicated, either.
First, have you ever played with one of those cheap, wind-up rubber band balsa planes? If you have, you probably have messed around with moving the wing forward or backward to get it to fly nicely. Too far forward and it climbs, stalls and repeats. Too far back and it noses into the ground. It does this because you are adjusting the center of lift of the airplane.
But, on most flying models (and the real deal) the center of lift is at some set point optimized to carry the load of the plane with a "sensible" fuselage length. and balance is achieved by distributing the weight of "stuff" in the airframe so that the center of gravity is just a bit forward of the center of lift. Without going into too much detail, you want the plane to be slightly nose heavy if you were to suspend the plane from its center of lift point (which is approximately 1/2ish the distance from the leading edge to the trailing edge of the wing - that distance is called the 'wing chord'). The horizontal tail surfaces are the 'levers' that hold the nose level in flight. Think about you and a much heavier person standing on a board that is on a fulcrum. In order to balance you with the heavier person, your side of the board has to be longer (farther away from the fulcrum point). On an airplane, that fulcrum is the overall center of lift.
So, you have a couple of options at this point. One, slap the wing on where you want it to go, then adjust the center of gravity by moving around the battery, adding a bit of weight to the nose/tail as need be. Or, locate all your components, then position your wing just behind the center of gravity.
While option 2 sounds reasonable, its just plain (plane?) silly. Go with option 1. Personally, I'm a huge proponent of, "if it looks like it should fly, it will fly." Position your wing somewhere between 1/4 to 1/3 the distance from the front to the back of the fuselage, then adjust the location of your battery to balance it out so its slightly nose heavy. If you support the plane with two fingers under the wings, it should balance with your fingers about 1/4 the wing chord.
Let me know if what I said doesn't make sense. I'm a teacher, so I'm used to reexplaining the thoughts that get trapped in my brain!