How do I number my pages on Microsoft Word 2007?

I'm doing a research paper and each of my pages have to have my last name and page number in the top right hand corner, but I don't know how to add it. It let me get the page number up there, but I don't know how to customize it so it has my last name too (Garnett 1, Garnett 2, etc). How do I do this? Thanks