Dual display

[Necrolezbeast]

I have an Albatron TI4200 128mb, I just bought a new monitor and am trying to get dual display setup correctly and can't quite figure it out. I've seen some people with a window open on one screen and the desktop on the other, how do I make it that way? All I can choose is vert/hor spanning and clone...I'm using the det4072's