Please take a moment and note how your joystick is assembled and all the parts that can be dettached. I recommend taking a few photos before dismantling it.

With the Phillips screwdrive unscrew the #1 to #4 screws in Fig. 1.

Using the Torx T10 head, unscrew the #5 (Fig. 1), #6, #7 and #8 screws (Fig. 2)

Screws 5 & 6 have a larger thread pace than 7 & 8, although the heads are the same. So please take care when you screw them back on (Fig. 3).

Using your hand, unscrew #9 (Fig. 2). Please note that you cannot completely remove this screw, but you don't need to do this anyway.