Define inlet and outlet on Inventor
 

Hello everyone,
I am traying to import my geometry from Autodesk Inventor to work on OpenFOAM. I know that i need to save the geometry on STL or OBJ, but first of that, i am trying to define the inlet, outlet and wall zones from my gemetry.
I was reading from other internet forums and watching videos, but i cant find a claear answer for my problem. If one of you know how to define the faces, i would be very gratefull.

Best regards.