Just place the embed code right into the Row inputbox:
This image is hidden for guests.
Please log in or register to see it.
Right click on your Youtube video in YouTube and select the option to copy embed HTML. The code should look something like this:
<iframe width="640" height="390" src="//www.youtube.com/embed/NnnSS0_-xoA" frameborder="0" allowfullscreen></iframe>