My personal website (www.becsta.com) is built using Wordpress, which I'm reasonably familiar with.  Wordpress is fairly straight-forward and simple.  It has a home page driven by PHP scripts, and formatted by CSS styles.  There are static pages, and dynamic articles, which form blog-like pages.  The placement of "modules" is also fairly straight forward, because the module code is placed directly into the page (well, most of the time a hook to some module code is placed in the page).

Joomla is quite a different beast entirely.  The main page is formed by blocks of module positions, and maybe an article or two.  Each module position is exactly that, just a position.  There's a very brief mention of the position name in the PHP code, which Joomla parses during page streaming, and running each of the modules in turn, which are responsible for outputing whatever they need to output.  

From a layout perspective, CSS is responsible for positioning each module block on the final page, so it becomes quite difficult for a punter like me to program a new module position.  It's pure trial and error!

So far, my bacon has been saved many times by a Firefox plugin called "Firebug".  It's just _awesome_ for discovering how pages are laid out, and great for on-the-fly CSS changes.  I can change colours of individual sections to see how they look before committing them to the CSS style sheets.  Great stuff.

Well, that's about it for now.