When you start up the PC after making the connections, the graphics card driver ought to detect that you have two screens attached, and show them in Graphics Properties. There you can set the resolutions, and depending on your graphics card you may have other options. Extended desktops can be fun: drag applications between screens, watch a movie on one screen while surfing on the other. With MS FS you can have the main window on one full screen, and instruments on the other.
