go to your homepage and at the top below your screen aviator it says add a widget, go there and find video. Once there it will tell you how to go to youtube and you can copy a video to the widget. The first couple of times I did this, it took awhile to click the right bottons at the right time, but dont give up, you just have to be patient with it. Heck I still have trouble with it sometimes in the copy part
also,,,I just remembered, some videos cannot be copied b/c of registered trademark stuff. Even after you have a video on your page, it can all of the sudden disappear, leaving you with an empty widget box.