New in the catia world

Hello, I am in the AEC world and coming from Archicad/Revit, jumping in the 3dx world, as a very new user, the edu space is not really targeted to my level. One module seems to be good, but I still have many questions ( why open a part design and then i have to add 3d part again? ) Would anybody recommend a book i can follow to understand the structure ? next question, my zoom does not work with my mouse need to use the view tab then click zoom, and has anybody set up a 3d space mouse to work?
thank you al, looking forward to learning a lot.