How to convert Stage to Stage3D accel. gfx?

Can someone show me, if possible, an easy method to convert pre-stage3D code to stage3D accelerated-graphics compatible code?  

Can you simply just create an instance of stage3D, and by adding an older, non-stage3D 'entity', thereby accelerating it's graphics, or does it need to be hardcoded every time (without an engine like away3d4.0)?

anyone wanna show me?  ;)