This seems to work automatically when in a side view (Like in the Kinematic Character example). All what is needed is a collider and the top body will move with the lower body.
But how can one do this from a top down view? A collider will prevent the top body entering the lower body.
For example, here, how could I move the Dinosaur and the Platform together?
Or 'tell' Godot the Dinosaur is 'on' the platform?