As an avid CC3 user with no cad experience, all I can say is 'FOLLOW THE TUTORIALS' they give you so much information, and now with smart symbols you pretty much know the template you choose will put the symbols on the right sheet/layer they belong.

As to add-ons, you realy only need the base CC3 program, but I find the Symbol Packs and the Annual are nice 'additions' to have as they give more options for the maps.