I think I understand better now.
I also checked Ari Danish's video about HDAs and it's clearly seen that when he switches between definitions only one definition is active it becomes green and every other is red. What it basically does is it sets the definition to all instances in the scene.
In my case it's not like this.
Somehow they are all allowed to be green and it's not setting up the definitions
![](/static/djangobb_forum/img/smilies/smile.png)