Carefully pull the shell off, as there are still cables connecting the two. The microphone(green) will probably hold the shell a bit back on the upper side, but just pull carefully. The microphone ist just lightly sticking to the white pad so you can just pull it off carefully. This will also make reassembly easier later on.

(Optional) Next you want to disconnect the ribbon cable connecting the touch pad. Its held on with small connector where you need to flip the small black plastic bracket upwards. Then you can pull it out. (Note: you can skip this step but be careful around the wires not to tug them.)

In the third picture you can hopefully see how the bracket is flipped up.