How can I reuse existing video files for different products?

[Old_Mill_Gift]

I have a video that I want to use on different products. In the media section of the product, I only have the option of Add or Add From URL. If I click Add, it only lets me upload a new file. The video already exists in Contents/files. I tried uploading the video, and it added another copy of the video. I read that there is supposed to be a "Select existing", but I don't have that option that I can see.