Creating a scene graph / hierarchy using an entity component system

Question

I do not seem to find any good resources on how to organize entities from an ecs into a scene graph / hierarchical structure e.g. for a 3D editor.

Im talking about something like:

-root
  -player
    -left-arm
    -right-arm
  -tree
    -branch

Could you give me a design example or maybe link some resource that explains how I could achieve this?