The steps i went through was as follows:

1) Download Map pack

2) Put game in and had to download a new patch

3) Go into game and install it from the multiplayer menu.


Thats it. At least thats how it was for me here in the US. You can always try and download it again. If you purchased it already, you can download it up to 4 more times so you might want to try again if you still cant get it to work.