I disassembled mine and took some photos for you.
This is the complete unit. The knob literally pulls off and there is a nut underneath to undo that holds the workings underneath in place. There are also 4 screws on the face of the device to remove.
This reveals the internals - and the knob should now also be free of the front cover of the device. Now the external green wire terminal just pull out again - literally just pull out and the board itself is held by two screws that need removed.
What you are left with is the actual parts you need that are at the bottom of this image and a knob as well. Everything else has little purpose. To mount the knob, all you have to do is drill a hole in your box to accept the it and use the nut taken off earlier to secure it in place.