How to know if someone stole your video ?

How to know if someone stole your video ? and... how to claim the money ?

First you need to find the person using your video and second you need to prove ownership of the video. if you can do those two things i think you should just follow normal legal action. I'm not a pro, but unless they're a big site i feel it might be hard to get money, cuz once people know trouble is around they corner they tend to take down the video or stolen content.