Follow the guideline below carefully.
Turn your laptop off and give it a few minutes to cool internal components.
Shut the lid and lay it on a clear surface with the back side facing up and unscrew it.
Keenly check if there are any restraining screws (some latest models of MacBook have them). Carefully remove the battery and you'll see the trackpad.
Improvise a raised surface, you can stack books. Put your laptop top facing down in a position where the keyboard is on the book and the screen is hanging.
Use a relevant screwdriver to remove all screws.
Detach all cables and remove the trackpad.