It all depends. There are the default shortcuts(Ctrl+C=copy for ex.) and there are user defined shortcuts thru Tools>Customize>Commands.For instance I put Ctrl+0 for Fit All In.
I myself I'm learning Catia now, but others members more experienced may point some other tips.
The procedure soy just discribed is an up and down mouse motion moving the mouse sideways as you hold shift and midlebotton with also update the camera.
To itsmyjob, clicking on the x,y or z (or u v w) symbol of the compass will give you the normal views; clicking the same symbol twice will reverse the viewpoint.