The helpers.php file
Every template file that is processed by PHP will have access to the helpers.php file that is included with ScreenSteps. This file has a couple of helper functions that will print out content for you. For example, it has a printArticleXHTML() function that prints the article as XHTML. It also has a function named printManualTofCXHTML() that prints the table of contents as XHTML as well as printArticleMarkdown() which outputs a Markdown representation of an article.
If you would like to inspect the helpers.php file then you will find it inside the ScreenSteps application folder on Windows or application bundle on OS X.
On Windows look in the ScreenSteps installation folder. You will find helpers.php in ./components/html_exporter/helpers.php.
On OS X, it will be located in the application bundle in the ./Contents/Resources/_MacOS/components/html_exporter/helpers.php.