For anthing you want to save, videos, images, articles, and links, all you have to do is click on the small green 'save' button beside or below the content you want.
You will find whatever you saved in your favorites located on your profile page.
When you are on the page containing the content you want to add to your favorites all you have to do is press the little green button that says save under the rating and it will be saved to your favorites :)