Here's the "deal" with Joomla....  Joomla is called a content management system, or CMS (there are others, as well), and these types of systems offer foks who know nothing about coding a website the opportunity to have a full-featured web site where the content, essentially, is simply typed into the page!  The content can actually be edited directly from a page, itself, or from an administrative back end.

By the way, unless you're something of a techie or have a lot of time on your hands I would strongly recommend Joomla over the other available content management systems (Drupal, for instance, is  also quite popular).  The reason is simple: Joomla is just simpler to use than the rest and there's tons of support, themes, modules, etc. Content management systems typically require a web server running PHP 4 or higher and a relatively recent version of MySQL (a database system).  Almost all web servers have these features to the extent that it's almost not worth mentioning. And, by the way, if you know some basic HTML the back-end of Joomla gives you the option to use HTML markup.  In short, the more you know the more you can do - but you don't have to know very much to put together a Joomla site.  By the way...

1. You can find a list of other content management systems here...., and
2. You can visit the forum for tips on a really basic Joomla setup (just getting things up and running), and..
3. I am eventually going to write a little "how-to" that, very explicitly, gives you a step-wise tutorial on setting up a Joomla site (a bit more organized than my random notes in the forum).