Slacken both the clamp bolts on the fork crown fitting and the pad bolt on the handlebar clip lug. Adjust steering head nut as required. Re-tighten pad bolt hard and clamp bolts on completion of adjustment.
It is important that these two clamp bolts (in the lower head fitting) are not over-tightened, as it is comparatively easy to deform the outer tubes by excessive tightening.
If the outer tubes become deformed by this over-tightening it will be appreciated that the rubber seal will not be able to hold either air or oil and deflation of the forks will follow.