ill upload a pic in a min mate of how gaz show you to assemble them and you'll understand

Gaz's picture \/
as you can see from the pic thats how you need to assemble them but ill take you through it.
you need to remove all parts to get the strut off i.e. track rod ends/ drop links/ wishbone. compress your springs and undo the top nut and remove all the top mounts and bearings, remove the spring then knock the gold thing that secures the damper to the strut off (anti clockwise) then remove the damper and your left with the black strut and the spring pan, you take the metal spring pan off by hitting it with a hammer towards where the damper was and it'll pop off (pic of the spring pan in question base of the spring)
a unassembled standard setup
then you'll have your coilovers will be a set like this (not necessary this setup)
You then put the damper in the strut and put the securing screw piece on, do this up tight and then screw on the 2 adjuster bits these are what your new springs sit on and are how you adjust them. then put the spring on then the top cup sits in the top, the bearings go on after that followed by your top mounts and the damper securing nut. (going to assume your using a standard setup i.e. not solid top mounts)
you'll end up with a setup that looks like

hope that clears it up for you bud