- The html5 tutorials has a sidebar list that allows you to open the tag description that you are interested in. It defines the tag, shows you an example and describes each attribute if any.
- HTML5 Tag Reference also has a sidebar list that allows you to open the tag that you are interested in. The home page shows you the new tags and tags not supported in HTML5. It defines the tag, shows you an example and describes each attribute if any. They also tell you the differences between HTML4 and HTML5. Plus W3Schools provides you with tips and notes on using the selected tag.
Until you have create a few HTML5 websites, you can use these resources to help you learn it quickly.