I had some screencaps on the first page of the thread. Essentially, this device:
It's not a trackball, but something that protrudes significantly from the indentation in the panel, possibly on a short stick; it's grabbed by the whole hand when operated. Impossible to tell whether the prop component was actually built to move.
FWIW, when we actually see piloting happen with the flat panel interface, it seems that the "up arrow" makes the shuttle go forward and the "left arrow" makes her take a banking left turn. Or at least that's the general gist of what happens in, say, "In Theory".