Gameobject into another Gameobject

Hi everybody, i’m new to unity and i’m just trying some functions atm.
There is a thing that i’m not able to understand also with guides, tutorials and docs:
How can i insert Gameobjects “B”, “C”, “D”, … into a GameObject “A”?
I mean something like the Flame GameObject provided with the standard assets. Flame is a gameobject with only Transform as component, and in the project hierarchy it appears to have 4 objects inside it, 3 of these contain components Transform and Particle Emitter and the fourth is a “Light” object with components Transform and Light. So 4 distinct gameobject into a parent gameobject.
I’d like to create something similiar, so that i can encapsulate in a single gameobject more gameobjects.
All this through the editor interface, is it possible?
I tried to drag an object “A” over another “B”, but the result is that the destination object just get a copy of “A” components.

Thank you

You are confusing Components and GameObjects. GameObjects contain Components. Transform is a Component. So are those other things. Transforms can also contain other Transforms (hierarchical parenting).

You can create an ‘empty’ game object (it will have a Transform, they all do), then add Components (from the Component menu, or drag/drop).

If you have something built up and want lots of copies of that, create a Prefab, then drop your game object onto that Prefab (in the Project view) and it makes a Prefab you can then drop lots of into your scene/hierarchy view.