Acadly, due to lack of resources currently, does not allow uploading massive videos as resources. Hence we support sharing YouTube links.
If you have a small video (less than 10MB in size), you can upload it as a Resource File rather than a video.
If your video is hosted on some other site (and not YouTube), you can share the link to the site as a Link Resource.
Going ahead, we would support more video players and would allow uploading videos.