Extract the files
 

Ok I've downloaded the campaign. Now I must extract the files. That's the point - to where?
Is anybody out there with a pure heart?

Try extracting the into the scenario folder of the game.

Yes, everything (including the .wav files) go into the Scenarios folder.

(Note there is another .zip file within the main .zip file. This one includes the standalone versions of the campaign missions, and should be unzipped into the same 'Scenarios' folder.)

Enjoy!