Unlike AutoCAD or some other CAD programs, you are not going to draw a box to define what area to print. You are going to use the actual drawing Window....hit the "Restore Down" icon in the upper right corner of the working window, (not the Revit program window, but the view window) between maximize and minimize. Size the window for what you want to see by dragging the sides or corner, and you may have to Pan your drawing to get the area you want to print to show in the window. Now, plot your drawing to "Visible Portion of Current Window"