I've never done this before.  In Photoshop when I go to create a new file I get the the pop up that lets me create the size of the "box" I want.  Once the "box" is created it has a white background.  I want to change the color of the "box."  Do I not do this  with the foreground/background selector? I'm trying, and it stays white.

Thanks...

set whatever color you want the box to be as your foreground color and hit ALT+Backspace

Ha!  I figured it would be pretty simple.  I just did it.

Thank you!