1. Add a Video Widget element to the selected canvas

2. Copy the Youtube video ID from the last part of your video’s URL.

3. Over in the right toolbar under the Video tab, set the type to "YouTube" and paste the end of the URL in the YouTube ID box

Now that your video is added you will have additional settings available for the video. 

You can set the Auto Play, whether or not the video controls are visible, set when the video starts or ends, loop the video, show the video details or show any related youtube videos at the end.