Thanks so much for your time to help me, but I feel ashamed to say that it did not help me yet.
I am trying and trying and can't solve the puzzle yet.
I have the feeling I want to use a tool that's not in the box (yet).
But I also have the feeling that the missing tool I can't find is something that is very useful for everybody.
I guess in many games, game builders want to put a random sprite from a Family (or a list or a folder) of sprites on a certain place (X, Y)
in their game and also need to know it's Local Variable.
It could be useful for appearing random all kinds of things on a certain place to make the game more interesting,
as when every time the same object is showing up.
And of course the game builder needs to know the local variables of it too.
But I can't solve this, and again maybe I look over it and there is a simple solution for it.
But I am afraid I want something simple which is actually very complicated...
I Thought to choose on the 'Add Event' side: System, 'Pick random Instance'.
I could choose only one item so I choose Family.
One would expect it would pick a random item from the Family (the collection of my sprites),
but it always shows only the last one of the Family.
Than I tried 'Pick by evaluating' so I did choose Family again and filled in my Local Variable: Name.
So this is not the way...
I guess I am looking in the wrong direction...
Could anybody help me or just point me in the right direction?
Thanks again Nimos and everybody else who wants to explain this to me.