The documentation you linked me from w3school. Also the documentation from the developer.mozzilla site, the unofficial documentation page for javascript.
Again, it entirely depends on what you want to do. You could recreate the video player from that documentation. Or, you could just target some elements with CSS to change the styling.
With your code above, you will not get a video player, just by setting a div to have a class of moviecontainer.
With all of that documentation , you have plenty of info to get started.