Yes , the user also wanted to learn how to add the videos to the page as in modules or some other form of embed onto the theme . It was a double question ;)
To embed the video in the widget you would use this code form Youtube when you click share on the video you like <iframe width="560" height="315" src="//www.youtube.com/embed/ZnSgg3irD3E" frameborder="0" allowfullscreen></iframe>
No you would replace the entire script with the embed code for the video which you get form you tube and then you paste it in that area replacing what is there . fromm < script > to < /script > you replace But you will need to use the stable version please.