This ⬆︎⬆︎ is excellent advice. I did excactly as Dorothy said. The screen disengaged from the case very easily.
The removal and installation went exactly as described, and the new trackpad worked correctly the first time. The toughest part - truly, not all that difficult - was manipulating the four screws that hold the trackpad in place. I don't think I've seen such small threaded fasteners since I went to a watch museum!