Before you go off editing pages, learn how to use WikiMarkup.

There is a EditThisPage Link at the bottom of every page (if your browser is configured to request pages in another language, "EditThisPage" will be called something else here). Just click on it to edit the currently shown page.

You'll see a large input box appear with the current content inside. Just make your additions or fix some typing errors and push the [Save] button.

You do not need to register or do anything else to use this function!

Now go to the SandBox or NotePad and play there a bit...