Not sure in your particular case, but generally there is a flat spring clip which fits over the ball and socket at each end of the strut. you may have to look carefully to find this.
once prised off with a small flat screwdriver blade or similar, the ball joint should pull apart easily.
Be careful when removing the flat clip as it can spring off and vanish who knows where. Try to keep one hand cupped rotund the action while using the other to hold the screwdriver.
Reassembly is the reverse. Put ball into socket and clip flat spring piece into place..
I've said ,flat, but it may be slightly radiused to follow the diameter of the cylinder of the strut. Have a very good look before dismantling and a phone on your phone may be useful.