Thanks Raildex_ for you answer.
I am not fully sure if I made an mistake on the video. I selected brewery 5 and try to add the event dispatcher from the list i get by right clicking the blueprintvisual editor. But instead of adding the selected event dispatcher “OnWaveSpawned” to the visual editor the editor only selects one of the existing event dispatchers in the level blueprint, like you can see in the video (2nd try).