How to upload intro video on landing page of site
If you're looking to add a video to your course landing page, you can easily do that from the course builder under Landing Page > Banner > Demo Video.
If it's the site landing page, that does require some savvy with HTML/CSS right now (we'll be working on making this easier later in the year, though)
I'd recommend getting in touch with our support team directly with the details and we'll take it from there. You can go here to get in touch with the team.
How do I delete the demo video from the landing page? I actually don't want it.
You can simply delete the url of the video so that it no longer shows up on your landing page.
I don't have the landing page button on my course builder page. My button says "Build Course Landing Page". My Landing Page has been built and saved and my course is published. When I go in through this button and click Banner, there is not option for a "demo video".
In your case, you are using the new Site Builder feature so much of this discussion topic would not apply. With Site Builder and the theme you may be using, the Banner section itself that is provided does not have a video option. However you can use a 'Text and Media' section to build your own version of a banner that includes video and buttons as you like!