The exposure is relatively simple - 30 seconds at f2.8 with the sensor rated at ISO 3200 or 6400. The camera does the rest. Turn noise reduction on if it isn't already and, yes, there's some noise in the photo, but it's small, contained and, frankly, I am incredibly impressed.
If you're worried about image quality, the biggest killer is movement. The slightest wind will move the leaves and grasses, so my approach to night photography in these situations is to go for mood and emotion, not clinical technique. As it turns out, there was hardly a breath of wind in the evenings at Karijini - we knew this because when driving along the dirt roads back to the Retreat, the dust would be hanging in the air from the car in front. No wind is great for night photography, but bad for driving!
The exposure straight out of the camera shows the Milky Way. Most of the latest DSLRs can capture images like these when you push the ISO settings up, but only the best of them produce such clarity. And you need a good quality lens.
Focusing at night can be difficult, so either you need a strong, bright torch so the autofocus system can lock onto something (such as nearby trees), or you can work out where to focus your lens during the day. The stars will be at infinity, but often you're relying on depth-of-field to keep both the stars and the land-based content in focus together. No torch will let you focus on infinity, of course. I found infinity on my 14-24mm zoom was just on the right edge of the infinity symbol. (NB Infinity focus is never all the way to the end of the focusing range with autofocus lenses, it's back a bit and the trick is to remember exactly how far back!)