How to use Feasibility/Optimization function through a feasible FEA result

I am using Creo Parametric - Release 4.0 (connected) Release 4.0 and DatecodeM100

I want to know how to use FEA results to optimize the structure design of a model. For example, i have already completed a FEA running with a feasible result. How can i use it in the Feasibility/Optimization function. Please give me an actual tutorial.