first you need a consistent anchor point. once you have this a couple of ways of aiming would be instinctive and gap.
In instinctive shooting you basically just concentrate on the spot on the target that you want to hit, draw back and shoot. the theory is that your brain and muscle memory will eventually take over, much like throwing a ball. If you want to try this you need to move close to your target and shoot a lot of arrows only moving back when you are consistent at the distance you are shooting.
the gap method, which I prefer uses the gap between the point of your arrow and the spot on the target you want to hit as a reference. theoretically you need to find your "point on" distance. this would be the distance at which you can draw and hold the point of your arrow in the center of the target and when you release, you hit where you are aiming. then as you move closer to the target you would hold the point of the arrow under the center of the target by a few inches and the closer you move the lower you hold on the target. if you moved further away from your point on distance you would hold the point of your arrow a little higher for each distance you move back. the problem is with the light arrows shot today the point on distance for alot of people would be 40-50 yards or so from the target which is too far for a beginner (or me, lol) to consistently try to shoot from.
If I were you I would move to within 10 yards of your target and hold the point of your arrow about 12-15 inches below the center, shoot and see where you hit. if you hit higher than the bullseye, next shot hold your gap a little lower. if you hit lower than the bull shorten your gap a little. try to concentrate on the center of the bullseye while checking your gap with your peripheral vision. as you improve and move back to longer distances you will shorten your gap a little at a time.
hope this helps and wasnt too complicate.