If you have the owner's manual, it should tell you how to do it. Look on the light cover, there are two indentions on each side, push them in and pull back. Cover should pop off.
If you're looking to take the whole light assembly off, you have to pull the deck cover. There are screws on the bottom of the light you'll need to remove to get the who assembly off.
I took mine off and did a DIY of vinyl tape and made a light cover. Printed an Audi logo from Google, laid it on the vinyl tape and cut it out.