Most basic elements like div blocks and containers have a transparent background by default.
The body element, however, has a white background by default. It looks like you changed it to transparent as well. The Designer’s Canvas is also defaulted to white, so even with all elements set to transparent, you will still see white.
Are you trying to get the video to stretch behind the “Stories worth telling” section?
If so, I think what’s happened here is you’ve misunderstood the meaning of the “container” element. What you need to be using there is a div. Take both elements there (bg video, stories worth telling) and put them into one div that is positioned relative. Then switch your stories worth telling to a div and float it left. Then take your background vid and position it absolute 100% 100%.
You’ll also want to take your Section 2 element and make it 100vw 100vh, instead of setting it to the size of the video. That’s going to get you side-scrolling, and you don’t want that.