Disclaimer: Is awful and probably shouldn't be used
The HTML file can only contain tags which have been defined in BaseTags.py or VoidTags.py (or elsewhere if you want to start creating your own modules and/or extensions). It should have most of the HTML tags commonly used (i.e. <div/>, <a/>, <h/>, etc.)
Basic use involves creating an instance of the HTMLGenerator class and then start creating instances of tag classes (e.g. DivisionTag()) that you want to add to your html file. When done, call the HTMLGenerator.saveHTML(some_name,some_dir) method and it will save it to the corresponding file, you can also use the HTMLGenerator.dumpHTML() to have the HTML text printed to stdout.
A basic HTML file is generally composed of two main tags, the <head> tag and the <body> tag. The <head> tag is kind of like a pre-amble where you can define basic global properties, and the <body> tag is where you put the stuff you want to get displayed on the page. The HTMLGenerator class has special methods for adding stuff to the <head> and <body> tags respectively, as it always creates them (i.e. you don't need to make those tags explicitly). Instances of the <head> and <body> tags can also be accessed via the corresponding .getTag() methods.
The make_html.py script shows an example implementation of the HTMLGenerator class.