To make new articles easier to edit, Preload templates have been created. If you are on the default Oasis skin, you should it on the right side of the content box. And if you are on Monobook skin, you should see it below the content box. This is a MediaWiki JS alteration and requires java to function. Though on Monobook you should be able to get the non java version to work just fine; it is located above the content box.
Where it says "Standard preloads", you can click where it says "(click to browse)" to pull down a list of templates. Clicking on one of them will place it on the page you are editing, rather than having to find a page that has the template.
Where it says "Custom preload pagename", enter the title of a page in the box to load all the text on that page into the page you are editing. You will probably very rarely, if not even use this button.