If you open the bonnet and look at the strut-top, you'll see a nut with a round metal plate under it. These hold the strut assembly to the car. You undo the droplink first, then the two bolts that hold the strut to the hub carrier, and then the nut at the top. Ensure that you are holding the strut securely as it's heavy!
Now you need the spring compressors. Omega springs are big, oddly shaped and powerful. If you don't have some robust compressors, you should seriously consider paying to use professional kit as you can really hurt yourself. The wimpy sets sold for doing mk1 Escorts and the like are not up to the job.
Once you have the spring securely compressed, then you undo the nut at the top of the strut, and remove the rubber top mount and the bearing underneath it. If you do nothing else before reassembly, gently pry the bearing apart to clean, inspect and grease it. As it contains about 2 dozen small ball bearings which you don't want to lose, I would recommend you do this job in a container. Something like a 1litre icecream tub is ideal. Clean the whole lot with your favourite solvent(I like thinners as it's cheap, effective and I keep it in stock, but a few squirts of brake cleaner or white spirit will do), and check that the metal races are not worn, and that the ball bearing are still evenly shiny. Then reassemble the lot with a bit of fresh grease. I found on my car that the bearings were dry, and caused a loud creak when the steering wheel was turned.
Then you reassemble the strut, which is the tricky bit if your compressors are small.
Refitting is the reverse of disassembly.
This isn't a difficult job, but good equipment and good practice are vital. Another pair of hands is useful.