Just like in AutoCad, you can click and drag with the middle mouse button to pan around in all three views (plan, profile, perspective). If you don't have a middle mouse button, you can use the Pan tool (four-direction arrow icon).


In the perspective view, you can swivel the camera by right-click dragging.


Simply zoom in and out with the scroll wheel


Holding the right mouse button while scrolling with the wheel has two effects.  In the profile view, it will change the horizontal-to-vertical scale ratio (this can also be set under the View menu).  In the perspective view, it will change the camera aspect ratio (experimental feature).