How do I create objects like on Space Shooter Template?

So, I've been using C3 for a year or so, and one of the basics to create a game is that you can only create and object in a layout if that object was previously present, even if it was destroyed at the start of the layout.

But I opened the Space Shooter Template ( https://editor.construct.net/#open=template-asteroid-shooter ) and the layout has almost no object placed, but when you run the layout it loads every object from the second layout.

How do I create objects like that?

After messing around for a bit, I think you only need to have one instance in the entire project to spawn a clone of it. I tested what happened when I deleted the asteroids, and then they didn't spawn. It doesn't have to be on the same layout, there just needs to be one in the project (I think).

Hopefully this helped.