I just replaced my last week. And I had same questions..
The thing is that you need to remove entire plastic from the OUTSIDE of the car.
So, here's how I did it:
00. FIRST, remove the key from the car and wait a minute or two for everything to settle down. I didn't do this and it was making beeps all the time.. later I figured and it was ok.
1. Inside boot, I have a little compartments left and right. Open the one you need and you will see black plastic wing nut. Remove it with your hand.
2. Also you will find electric connector, you need to plug it out. Not an easy task, be careful, and slowly disconnect it. You need to push the ends to release it.
3. Now go outside and slowly, gently, try to remove entire plastic (armature) of the car. I tried slowly and noticed it will go. So I kept going left-right until it went out of those plastic pins. There are 2 pins I think, and you have to pull it of by force. Just slow and gentle, and it will be ok.
4. Once you have this, put it on a table and you will see it's very easy to remove plastic cover from behind and change bulbs.
5. I also sprayed a little wd40 on contacts before I connect them back, to clean them since it is common thing to cause problems.