You need to make sure that your SCCM will support CC. If you have DIS and MFSW, then you should be ok, but VCDS will confirm what module you have. If the module doesn't support it, then you'll need to change that.
You will need the CC stalk, lower steering wheel column and a repair wire.
Finally you need VCDS to code it all in.
There are lots of guys on here who can fit it for you and who can do it in their sleep, at better prices than you can find at garages etc.