Building Windows 8 Metro App on Windows 7 with Visual Studio 2010

Question

My Visual Studio can't seem to build any of the Metro Sample applications. As I've never really used this IDE before, I've pretty much given up.

Can anyone direct me to a sample application that is already built and preferably some source code along with it for reference?

Note:

I have a copy of Windows 7 AND 8. However I can't seem to build Microsoft's File Access Sample in my copy of Visual Studio 2010 Ultimate. I'm trying to test one of my Win7 applications in Metro mode of Win8 (the application may be called for use during a user's session in a given Metro app).