beginner which software for createbot max

Hello all i recently convinced my work to buy a 3d printer. I got a createbot max with 250x280x400 build space dual extruders, heated baseplate and sd card input.

http://www.aliexpress.com/store/prod...817496292.html

I have never used Cad before and i am looking for a good software program to design basic items such as hollow balls bowls etc and sculpted things like dog bones i would like to later on move into more complicated stuff which uses two types of materials in the one print and objects that would need support structures.

I have autodesk 2015 on my mac but that is something pretty advanced and i would be looking at learning later on for both printing and having things cnc or laser cut.

Thanks guys!