1. In the directory on the left, navigate to "Trailer Loader" under the "NOT LINKED" subheading
  2. In the top-right corner of that page, click "Add Images or Video"
  3. Select "Images"
  4. Upload the poster for the trailer (white square box on the left)
  5. Click the "Options" tab in this dialogue window
  6. Find "Clickthrough URL" and select "Click to add URL"
  7. Copy + paste the youtube link to the trailer, hit save, and you're done!