Each version has a different set of things you can do to it. Make sure you choose the correct one so everything works correctly!
We're focusing on perfecting our articles for 12.04 LTS and up.
We currently do not have any plans to cover earlier releases. However, you can try checking the archives for earlier versions of our website that supported 11.04 and 11.10
Open your terminal (Ctrl+Alt+T) and type lsb_release -a into the box. Next to Release you'll see the version of Ubuntu you are using.