Several categories of tools are available for efficiently moving to specific locations and changing the display in the map viewer.
Slide the scale bar up and down to zoom in and out respectively, changing the map extent.
NOTE: the map scale and coordinates are visible in the bottom left hand corner of the map viewer (example below) and change accordingly when the scale bar or any other navigation tools are used.
To zoom to the initial extent of the map, click the Default
Extent 
icon located in the upper right corner of the
map title bar.
To zoom to the previous extent of the map, click the Previous
Extent 
icon located in the upper right corner of the
map title bar.
To zoom to the next extent of the map, click the Next Extent 
icon located in the upper right corner of the
map title bar.
Zoom in - Hold the SHIFT key while dragging a box on the map.
Zoom out - Hold SHIFT and CTRL keys while dragging a box on the map.