I would like to sell a film and then add the Option of buying (eg) The BTS video, etc. How do I do that so they can buy the feature for (eg) $25  then add the BTS for $5. I do not see the option of installing a file into the Options area(even a small one) - I could do this with Zen Cart.

Also there is a photo of an Add Media Button (in the manual) but I have the latest version and when I expand this does not show up (?)