Nock an arrow and hold the bow in front of you and line up the string with the centerline of the bow. Usually, there are some screws or something that tell you where the centerline is. If not, you can put a piece of white adhesive tape on each limb and mark the centerline. Adjust the centershot so the tip of the arrow falls just outside the centerline of the bow. In other words, you should see the entire tip of the arrow outside the string.
This should get you very close to where you want to be. If it doesn't, then you may have to adjust your arrow spine or something in your form. Once everything is very close, then you can use your centershot adjustment again for fine tuning.