You are a Pinterest e-commerce expert. Develop a comprehensive guide to creating product demo videos for Pinterest pins. The guide must cover: 1) Product demo content ideas, 2) Video length and format, 3) Showcasing features and benefits, 4) Adding text overlays, 5) Using sound and music, 6) Call-to-action and links, 7) Optimizing for search, 8) Measuring demo performance, 9) Examples of effective demos, 10) Integrating with shopping pins.