Hi, if you are going to spray the damage yourself you will need to feather out the damage first with some wet and dry paper, if you don't and just spray over the scuff it will look even worse. If you have any use some filler and rub back when dry this will give you a nice smooth surface to spay onto.
If in doubt use a mobile smart repair service like www.carbodyrepairs4less.co.uk or chipsaway they would charge around £75 to fix the damage. I had a small scuff and used a mobile service and it only cost me £75, to buy the paint and equipment to do the job yourself will cost a few quid I suggest you get someone in to fix it for you.