easy peasy.
take wheel off
undo the two bolts going horizontally holding the bottom of the strut in.
undo top mount under bonnet
get a bar under the chassis rail and lever the hub down then wiggle the strut out.
assemble the new replace put the coilover in the same place as where the strut was. do up the bolts then you will have to get them setup at the right height, camber, tracking and all of that.
Where are you mate.
Might be able to help you out if you are near the midlands?
well you will probally keep your old top mounts which are a rubber ring with a nut in it. i have seen that you can buy new top mounts but i dont know whether they will give any benefits?
also on the standard struts there is a clip holding the abs wire? or a wire going to the brakes. you will need to unclip this before removing the strut and try not to damage it. when you put the new coilover in im assuming it will not have a clip for this wire so you will need to cable tie it or make sure it is secure and not rubbing or trapped in any parts.
also you will need to grease the coilovers i think? some one who has them can advise you on this. basically its to stop them siezing and preventing from winding them up or down?