It's not that simple for me. If you can show us how to do that (suppose that your audience knows how to use your web browser developer tools, ffmpeg, curl, ...)

It's not that simple for me. If you can show us how to do that (suppose that your audience knows how to use your web browser developer tools, ffmpeg, curl, ...) for a few websites like youtube, udemy, nbcnews.com, ... that will be grateful.