You can change the view of your plot by using the View.. menu items or their corresponding Speed buttons. Choices include Zooming in or out, changing to World maps, backing up to the previous view or the original view that your plot started with.
To zoom the plot to a smaller area use View..Zoom-In..Drag Box w/ Mouse or View..Zoom-In..Dialog Lat/Lon Entry. If you are using the Mouse option, simply use the Left Mouse Button to drag a box to define a new area within the current plot area. The Dialog Entry option accepts latitude and longitude limits in decimal degrees, with precision to thousandths of a degree. Use negative numbers for west longitudes and south latitudes.
Use View..Zoom-Out to change the plot area to progressively larger (by 50%) plot limits.