I have just spent 6 weeks in Joomla land so I know where you are coming from..
Unfortunately there are no module check boxes in the mage ...
However, balancing the steep learning curve is the very logical (don’t laugh..) structure and the clean xhtml output.
This may help…
The Structural Blocks(user positions?) are defined in app>design>frontend>*Your_int>*Your_theme>layout>****..xml
start with page.xml , catalog.xml
This includes adding items to header ect.,
Pages are \âbuilt\â using these blocks by the 1-column.phtml, 2-column.phtml ect pages
The Structural Blocks contain Content Blocks which depend on what type of page you are viewing
(You can include and remove these blocks via a page\âs custom xml update or the xml layout page)
These Content blocks contain the \âlink\â to the code ( phtml file) eg
<block type=\"catalog/navigation\" name=\"catalog.topnav\" template=\"catalog/navigation/top.phtml\"/>
means app/design/frontend/*Your_int/*Your_theme/layout/catalog/navigation/top.phtml placed in the the topMenu block
eg Top Menu.
To create custom Top menu edit top.html
Total remove it by commenting it out in page.xml
Sometimes the phtml files contain more blocks that include other phtml files
but hopefully you get the idea
Have a good look at the admin back end with sample data -Save many hours by using rather than re-creating built in features.
create some test static blocks and CMS pages, play with the catalog, products and attributes