Its basically a copper tube or a lumberjack style copper ‘saw’ (which does not actually have teeth) + a guy consistently adding sand.
The tube drills were used with a contraption resembling an archery bow somewhat, with the string looped around the tube, such that you could draw the bow back and forth to ‘drill’.
There are multiple, detailed, hieroglyph inscribed picture/diagrams showing how this was done, made by people commemorating the construction itself.
Archaeologists have even reconstructed and tested these methods in our time, and big surprise, they work.