The YouTube Search window should open when you've installed the two modules you get from the ZIP that you download above. If it doesn't, open it from the Window menu. Type something in the window and press Enter. The Navigator is opened as usual, via Ctrl-7. Here's how it all looks:
When you double-click an item in the Navigator, the browser opens and the movie is displayed. Then you can watch it. Once we have an embedded native browser component in the IDE, you'll be able to set that in the Options window, then you'll be able to watch the movie inside the IDE.