If I understood correctly from the voice over on the broadcast, the whole process was commanded, step-by-step, from mission control in Beijing. First they unlocked the rover wheels, then disconnected the cable to the lander. Then they commanded the rover to drive out onto the transfer ramp. It sounded like the first commanded drive was slightly short; they commanded another few centimeters of drive to place the rover in the correct position on the ram. Then they commanded the ramp to lower. You can see on the animation immediately above this paragraph how that seems to involve a wire -- presumably the weight of the rover carried it downward as the wire was reeled out. Then they commanded the rover to drive forward and on to the surface.

According to what they said earlier today, there will be an event 24 hours after the landing where they unveil the first images shot by the rover of the lander, and vice versa. That will be our first chance to see photos from science cameras. I look forward to that!