before you start check the fittings below and make sure you have the tools needed to undo the top and bottom nuts and bolts.
You dont need to jack the car. The rear springs will take the weight. Look into the wheel arch on top of the wheel youll see the air pipe with an "R" clip fixing. Remove clip and pipe.
Open the boot, on top of the wheel arch is a rubber boot covering the shock top nut, remove. Undo the nut, you will seed a smaller spanner(or whatever the fitting is) to the hold the shock shaft still while you turn the nut. Be carefull at this point to note the order the various washers and rubber parts are fitted. Youll need to replicate that order on the new shock, which may or may not have all those parts with them. Re use any you dont have.
Get under the car and undo the bottom shock bolt.
You may need a socket and ratchet for these. Depends if the cup/bolt protector is fitted, mine only had one for some reason? Anyway, remove the bottom bolt and pull the shock out of the inset recess, may need a hammer or lever if its sticks, mine just pulled out.
Fit new shock. From memory.... Iirc extend the shock shaft to full length and push it up into the top shock mount, then, with bolt in the bottom shock hole ready, push the body up until the bolt is at the correct hight and screw the bottom bolt in. Then fit the rubbers and washers in correct order and fit the top nut.
Re fit the air pipes and R clips. Re double check all the bolts are tight. Then start the car and sit on the boot ledge feet on the floor, and wait for the air pump to kick in to fill the air bladders, you will then feel your feet and legs gradually drop as the car rises. Job done. :-)
Note, working from memory. So may have missed something but its basickly top and bottom bolts and air pipes. What ever order you find things assembled in, obviously repeat when refiting.