Scale
Sets the physical size of the artwork as a percentage of the original size to the page size being printed on i.e. the scale. To set a specific size select User Defined and set the width and height which will provide the scale as a %

Position
Sets where the artwork will be printed on the page. By default this is set to Center to Page. To reposition the artwork either click and drag with the mouse (in the preview area) or select User Defined and set a Top and Left position (as shown above).