Start from the POWER CONNECTOR - this is where there are no clips.

I’ve found out that my left button was getting stuck because of the rubber feet falling off the white plastic back cover (when disassembled). The click is actually produced by the pressure of the two rubber feet at the bottom of the trackpad to the desk. If one of them is getting stuck, the click will get stuck as well. This is where adjusting this screw does not help (although I’ve improved my click a lot). In my case, I’ve used just a touch of glue to glue the outer rim of the rubber feet with the white plastic inside. Basically when you lift off the white bottom piece, no rubber feet should fall off on its own. If one of them does, then most likely you will have the same problem as I did. Gluing the outer rim of the rubber feet to the white cover perfectly fixed the click getting stuck in my case. In opening up the device, you might want to consider heating the plastic back with a hair fan for a bit to get the glue going, it makes it a lot easier. Hope this helps someone. Thanks for sharing this tutorial!