Help Installing / Getting Started

[eluser]rizlmilk[/eluser]
I am trying to begin learning CodeIgniter but I am running into some difficulties. I have uploaded all CI files into a folder called 'codeigniter'. I then went into the 'system/application/config/config.php' file and made $config['base_url'] = "http://blowthecart.com/codeigniter/'

Then I followed the first video tutorial on this site to set up blog.php and print Hello World but it is showing a 404 page. I know that CI is working to some extent because it is outputting the 404 page.

Any ideas? This is my first time using a framework so I'm probably overlooking something. Thanks in advance.