Once you have the sample site up (you did follow the advice to install the sample site, didn't you?) you can get the feel of how Joomla goes together by enabling and disabling components until you get something approximating what you want your site to look like.
Remember that the content doesn't matter - that is a completely seperate issue from the site design.
Joomla Administrator
You access the administration system by pointing your browser at http://siteURL/administrator.
Configuration file
Some of the changes you make will need to be written to configuration.php, especially when you alter the Global Configuration. Do check that you see the message:
The global configuration details have been updated
If not, you probably haven't got the correct permissions on the file. On Unix servers, use chmod to amend the permissions, thus allowing the Joomla administration account to update the file.
