I have walked up both from Oxley Lookout (light green on the map) and from Endeavour Park (dark green on the map). Either way, it is quite a climb. Take plenty of water with you in hot weather, and don't over-do it.
Due to the windy nature of the tracks (especially on steep sections) and the overhead tree cover, you may find that the track files (below) do not exactly match the trail at all times. The trails are quite well marked, so you should not have any problems.