You don't need to disassemble the foot. Only the moving head has to be disassembled.
Put the camera on a flat surface like a table or floor, like in this picture and press on the point with your hand or foot until the two parts separate each other. Pic Then open carefully the rest of the front ring.
After that you have to loosen the 3 screws. Take the silver one and one of the black ones out. The other has only to be loosen. Then remove the black camera head. If you can't remove the black camera head remove the other black screw.
Now you have to unplug all cables you can see. Microphone, lower motor, power connector, upper motor and the cable for the IR LEDs.