So the Scots are voting today. If you want to get a quick overview of what this is all about, I recommend to start with John Oliver’s show Last Week Tonight:
A shorter but as well entertaining video was done by The Guardian, I cannot embed it, so here is the link.
Furthermore I recommend to watch the videos by the fabulous YouTuber CGP Grey. The first one is about why Scotland joined the UK at all – and the second video is about the difference between England, Great Britain and the United Kingdom.