Hello Alan,
your question is a bit too generic to answer with any specificity, but I get the sense you are looking to use Node similar to how you would Apache(+PHP/etc)? i.e., a generic web server with some back-end scripting. With Node, in order to do that, you should consider a framework such as Express that lets you add some of that functionality to Node by giving you a way to serve static files, use templates, return AJAX data using routes, etc.
—ravi