Node.js trouble

I'm trying to get started with node.js, but I'm in no way an advanced programmer. And I've never used cmd other than to check my ip.

My problem is I don't know where to save the files, and how to run them from cmd with node. The tutorials I've found seem to assume I should know all this without explaining it, and jumps straight to the code.

So, how do I actually run something in node? This is what I've done sofar:

1. Downloaded the windows installer from nodejs.org.
2. Installed nodejs in the default directory: C:\Program Files (x86)\nodejs.
3. Made sure I have Python and Microsoft Visual Studio.

And this is where I'm stuck, how do I test this?

1. It wont let me save files in the nodejs directory (even as administrator). Where do I save my files?
2. What would be the correct command and path in cmd to start node and run my files?