Grease Pencil on imported 3d Model and export file

Hi, I’m new to Blender (2.80) and I’m sorry if I turn to the wrong forum section.
Mu help request is for the following problem:

  • How to import a 3D model into the 2D Animation worktable and work on it with the Grease Pencil (on the 3D surface),
  • Export the 3D model edited with the Grease Pencil tool.
    Any help please or videotutorial?
    Thanks.