Headlines (<h1,2,3,4,5,6>) should always start with the highest order (<h1>)
and structure a document. It is forbidden to skip levels.
It is also forbidden to declare any attributes on the header tags.
<h1 id="foo" data-noise="loud" >Main Topic</h1>
Also note that headers should not be manually numbered. Both the numbering
of the headers in the document and a generated table of content can be done
automatically via CSS stylesheets. This way adding content does not require
changing subsequent manual numbering.
<p>This HowTo teaches you how to write content.</p>
The example uses a headline and the description is not giving any information
on what is really contained in the document. Summarize the key content the user
can find here. Don't repeat the title or meta description.