How can I change a Word document’s background to Olive Green?

http://ift.tt/1iZHv9S

I’m preparing for a competition of Microsoft Word organized by Certiport, and there’s this one question that I never get it right, and I can’t find any information regarding this, either online or offline.

It’s how to change the background of a document so that it is Olive Green, Accent 3, Lighter 60% with a Light Horizontal pattern.