Melody -MercurialIN said:
For youtube videos - on the Guide page of the UI - there is a toolbar with 'Featured', 'Top Videocasts', etc. Just click on YouTube, then you will see a list of the standard feeds. Just click the + button on any you want to show up.
There are a lot of different ways to add Favorites or Playlists or even just single YouTube videos - depends on what you are trying to get