Hello Hung The,
The video is set already, is it not correct? Here is what I have done:
In the Homepage there a module at the top with the revolution slider.
In the revolution slider, in the first slider I click in “Slide options”, “Background” and there I put that the “Type” is “Youtube video” and the Youtube ID of the video. Do I have to do anything else? I followed the instructions here: https://www.themepunch.com/slider-revolution/slide-background/
Thank you.