Yup, that's pretty much it. At least that's how it worked for me with Joomla.
1) Download the .zip file. 2) Unzip it. 3) FTP it to the server and directory of your choice. 4) Set up a MySQL database (nothing in it, just set it up and get the database server address, name, etc). 5) Run the installation routine by launching a particular URL.
It was pretty easy. The hard part, for me, is figuring out how to use the system. Once I can grok the idea of menus for everything, then it should be extremely easy to use and maintain. This menu thing is the only problem that I'm having trouble grasping (mostly how they interact with content and other menus) - and I suspect that I'm missing something very basic. Other than that, everything is a breeze.