HTML files are just normal text files... they usually have the extension of .htm, .html, or .shtml. HTML documents have two (2) parts, the head and the body. The body is the larger part of the document, as the body of a letter you would write to a friend would be. The head of the document contains the document's title and similar information, and the body contains most everything else.
Example of basic HTML document Structure...
Body goes here
You may find it easier to read if you add extra blank lines such as follows...
Body goes here