Revit to 3D max to Unreal

Good Morning. I have a major problem in passing a REVIT file to Unreal Engine. I think it is a common problem but I am looking for tutorials, but I can’t find any. When passing the Revit file, Unreal does not recognize the faces of the polygons nor does it separate the faces of doors and windows (Revit families). How can I adapt the model so that Unreal recognizes it? Do you know any link to a tutorial? Thank you!