Get a steel tape measure and laid on the floor measure between the front inside edge of the wheel rims ay as near axle centre line as you can. You don't need the actual dimension so use the back edge of the tape body on one rim, lock the tape off. Now do the same thing on the back edge of the rim, though you won't be able to get quite so high up as stuff is in the way. Because you locked the tape off you can then tell which way to adjust. If the tape is too short adjust the track bar inward so that the gap is half what it was. Then re set the tape and check it against the front edge of the rims. You are aiming to have the rims parallel. That is a very wordy way of describing quite a simple job. Centering the steering is equally easy to do but wordy to explain.
