iPhone navigation in tab bar

I'm new to iPhone development, and I wanted to create an app with tab bar and navigation.

I came across an article that helped me to achieve that: http://www.devx.com/wireless/Article/45161/

However, I got confused w开发者_JAVA百科hy we need to create a new UITableViewController subclass, but not program directly in FirstViewController? Which seems no use but just for tab bar. I actually tried that but not work.

Please kindly read the article which is simple and help me to understand that, thank you in advance!

You did understand, as you said: The FirstViewController is just there for presentation reasons. For showing an example of a tabbed UI you should have at least 2 controllers. This is what the example teaches you.