You can find all the downloadable product walkthrough videos on each of the product pages within Marketplace. Just go to Partner Center > Marketplace > Discover Products and search for the product. You will find files to download under the Files section, which includes an Express (when applicable) and Pro demo!
This is always the place to go for the most up to date content. Let us know if we can help with anything else! I and the other Product Marketing Managers would love to know.