trying to understand website template video player widget

[Hellblazer]

Well afaik, there are some ways to do it. Firstly, you need to design a script for your own website (if you want to make one) using some particular language (HTML more or less) or use a hosting website (php). Video player; there are several ways to do it. Something you could do is upload videos into popular video hosting sites like youtube, vimeo (thats the one used in the website you linked i guess), then share the links using specific 'video' tags that directly add a widget into the website you want it in. Other way is that if you have your own server hosted or some such, then you can use another 3rd party video player to directly upload the videos and host them on your site. There are several you can find, for example, Flash, WebM etc. Also, the recent development in HTML5 allows you to directly add videos rather than depend upon other 3rd party hosts and stuff. (so youtube shifted from flash to html5) Although it is still in development. You can also use JS, but about that i don't know of much. You can design web applets using it, so should work.
I hope i answered your question.