adding a rounded edge to a 3d Primitive in ProAnimator

Forgive me if this is obvious to seasoned ProAnimator users, but I am trying to make a 3d primitive with a rounded or beveled edge. I create something like a pyramid with four sides and want just the corners leading to the point to be rounded. I then want to use a square box and round the corners of only the sides and place these two objects together to make a drediel. Any tips on adding and adjusting corners of 3d primitives?

Thanks
Tim