More unfortunate problems-top case
Well, thanks to the helpful community here I got the top case attached properly. However, in the process of removing the top case, it seems that it is now damaged. The KB and Trackpad did not work. So I disassemble again, then the power button does not work. I examine the ribbon cable, and it has a crack running through it where it folds, and it was clearly cut.
I realize I have no other option but to buy another top case, but I just thought that I would post here to see if there is any specific thing I should do to protect the new top case.