Not sure about the 747, but here is the answer for the 767, I can only imagine they'd be quite similar if not the same.
Selection of flaps 1 commands slats to move to mid-range position, flaps remain up. Selection of flaps 5, 15 or 20, commands slats to mid-range and flaps to selected position. The inboard ailerons droop in conjunction with flaps extension. Selection of flaps 25 or 30 commands slats to landing position and flaps to selected position.
Another interesting point is with flaps in 25 or 30 (in a -300) if you exceed the speed limit the flaps will automatically retract to position 20, and extend when speed is below limit.