If you have the graphics hardware to support this, there are basically two ways to go about it: You could go to the program settings in Movie Edit Pro and use a suitable preset under the "Display presets" tab, e.g. "multi monitor with maximized video monitor". If your graphics driver is set up to function as an extended workbench, you can also stick with the default display preset and instead just break up the standard layout in Movie Edit Pro (e.g. by pressing "L" on the keyboard) and then drag & drop the preview monitor over to your second monitor and maximize it there. The media pool/file browser can be disabled if not needed ("F" key). This will give you the timeline and your editing interface on the one screen and the preview monitor on the other screen.

I hope this helps.