I can't find out how to start filming... or is it not that kind of addon?. need helP!

If you want to record your game play, then you will want to look into something like Fraps. Google it, and it should come with documentation on how to get it running. I am unaware of any free software that does the same thing (Fraps will work as an evaluation copy, but imprints it's logo across the top of the video).