Adding a Call-to-Action overlay to your video is easy. First, run a campaign to promote your video on YouTube. Then, go to the Video Details page under My Videos and fill out the fields in the section marked “Call-to-Action overlay.” All you have to do is include a short headline, ad text, a destination url, and upload an optional image, and the overlay will appear whenever someone watches your video. Clicks on the overlay will be tracked in YouTube Insight.. Full Article