How do they speak so fast oh my gosh? Can so somepne please explain?

Yes, I totally empathize with you. Believe it or not, after some time you won't even notice how fast they speak anymore. Just stick with it. Also, I notice you tried a C1 exercise. Try an easier level.

I dont understand

You can adjust the playback speed.  I listened at 75%.  It helped some.  In my experience. documentary films usually have a slower pace to begin with; but not this one.  C1 is a stretch for me, but why not stretch, once in a while.

I know . . .  It's so frustrating.  The French are behind the times with respect to the concept that slower speech really helps the non-native speaker.  I've expressed this to many French friends and French instructors over the years and they just refuse to concede this truth (French stubbornness I guess).  I also love how "easy French" videos and lessons are often very difficult for the beginner.  Usually, the response is "well, we want to make it authentic."