In the world of 3D, users are able to organize their scenes by creating a hierarchy. The hierarchy is created through the process of parenting objects to one another from inside the Explorer. To do this, simply select an object in the Explorer, then drag and drop it onto another object. Now you’ve created a Parent and Child relationship between two objects.
You can take this matter even further and make a Child become a Parent of a third object. This is a good practice to keep your scene hierarchy organized.
When an object becomes a Child of another object (Parent), it will follow all transformations applied to the Parent. This is useful in the case where a character or 3D object has multiple parts and needs to move around in the scene. That way you only need to animate the Parent model and the Child objects will follow automatically.