Blogs MU: Featured Video

In the menu, @ Theme Options > Featured Settings > Featured Intro Block Style
an option is to use a Featured Video.
This post touches on it
https://premium.wpmudev.org/forums/topic/blogs-mu-featured-page-on-home-page#post-121677
but I still don't know how to use that function. Do we upload it with the image loader? What is the recommended size? or do we just put a video on a post and designate it featured somehow?

Thanks
Troy