Render complex 3D meshes with pure ECS

Hi
I'm interested in how can we render complex meshes (meshes with many parts and many materials) in pure ECS. I try to use RenderMesh component, but the result you can see on the screenshot (there needs to be a car model like you can see on the background).

Code that I use

Code (CSharp):

1. _entityManager.SetSharedComponentData(newCar, new RenderMesh
2.             {
3.                 mesh = carMesh,
4.                 material = carMaterial
5.             });

So, my question is:

1. How can I get mesh and materials from the FBX model that been imported into Unity?
2. How can I get mesh and materials from the prefab (only mesh renderer component, I don't want to convert prefab to an entity, I just want to copy prefab appearance to my own entity)?

Thank you very much for the help