To separate the two parts that make up the mouse, help yourself with a card or iFixit Opening Tool, mainly in the front part, and the side that does not have buttons. Then the back, and finally the side where the side button is, be careful when lifting these two, as they require a slight movement.

Note that both parts are connected inside by a ribbon-type connector. Do not abruptly separate them.

Carefully separate the parts

Lift the plastic latch to release the ribbon cable.

Disconnect the ribbon cable from its socket.