Zoom - Allows you to select an area on your plans which will be zoomed to fill your screen area.
Fit to Page (Zoom to Fit in 9.2 and earlier) - Re-sizes the current plan to fit in the edit window (you will also see Sheet Size information above the plan, Measurement Type below it, and the current scale in the upper left).
Zoom to Max (9.3+) - Re-sizes the editing screen to show the entire editing space boundaries, even the space outside of the current plan, including the page information.
Zoom In - Zooms into the plan, centering on the center of your desktop. You can also Zoom in by rolling the wheel on a wheel mouse up.
Zoom Out - Zooms out of the plan, centering on the center of your desktop. You can also Zoom out by rolling the wheel on a wheel mouse down.
Pan - When selected, you can left click on the plan and drag a different part of it into the current view. You can also Pan by clicking and holding down the wheel on a wheel mouse.