The video element can be used to add videos to your publication. You can add a video from sources like Youtube or Vimeo.
To add a video to your publication, simply click the add button and go to the images section. Click and drag the video content block into your publication. In the configure tab on the right panel, you simply paste in your Youtube or Vimeo video link and configure its settings.
Be sure to also read about the browser policies on autoplay videos.