A supporting document is any additional resource that goes along with your video. For example, you might use it for a guided notes sheet that viewers fill out while they watch your video. You might also include a handout for the viewer to use in the classroom after watching your video.
While you can use a resource that already exists in your store as a supporting document, it’s important to clearly link the two resources in your product description. Buyers should be able to easily understand that they can get that resource by itself or purchase the resource and video together as a bundle. Please see the bundle FAQ for more information.