The Video Element.
The Video Element allows you to drop in any video clip from YouTube or Vimeo, and customize every aspect of the viewing experience. Set exact size and position of the player, name the title to improve and optimize SEO, set button colors, set properties for the fill, stroke and shadow of the player itself.
First, paste here the video URL you copied from YouTube.
Use the right side control panel to set the video properties. You can Hide the controls and make the video Auto-Play. This is especially useful if you'd like to make a video background.
To do so, simply go to the Position section on the right and you'll be able to set the video on Fit To Width / Height.
Note: Using very high resolution videos for video backgrounds is recommended.