Use SketchUp: AutoCAD for MAC can create the shapes but you won't be able to render it or apply any materials to much.

To learn AutoCAD for MAC in general, online tutorials from Autodesk are a good place to start https://www.youtube.com/results?search_query=autocad+for+mac+tutorial+for+beginners

Oops, one more link https://www.google.com/search?q=autocad+for+mac+3d+tutorials