Replacement Trackpad doesn't work

What does it adjust?

The green screw adjusts the point the down pressure click is reached. You should hear the click and the system should respond to that point as well.

I often find when I replace the trackpad I can encounter it rubbing on the sides. To help prevent that I use a Post-It Note on the inside surface of left & right sides of the hollow with adhesive side to the case. Then carefully tighten the Orange screws and pull out the papers. This makes sure there is a gap between the sides.

The old trackpad is back in and works but it is lacking in functionality.

@Tim Harding - Define what you mean by 'functionality'

The curser moved left to right as well as up and down across all parts of the surface? Does the click action work at the lower center point as well as the bottom left and right corners. Two finger actions also work?

The reason I wanted an upgrade was because I could no longer drag and drop. Click action works on my old trackpad in all areas as well as two fingers action. On the new trackpad I could move the cursor but click and tap were non functional. The cursor would not make the dock appear nor activate drop down menus.