Mr. Lu Miao

Hello I am going to build a parametric model of wheels from my stl file, and after importing the stl file in CAESES, I have no idea how to define some parameters, like the wheel radium, wheel width , wheel rim and spoke geometries and so on, And I didnot find any tutorials relating to build model from a stl file. So could someone give me some tipps thank you very much Lu Miao