You just add "ss" after "https://www." of any video url which you want to download.
For example i want to download a video from youtube: https://www.youtube.com/watch?v=olFEpeMwgHk
Now i add ss after "www." and enter.
The downloadable url will be: https://www.ssyoutube.com/watch?v=olFEpeMwgHk