From the Wiki I get you should use Game Creator → Dialogue → Actor to create an Actor.
This does not exist for me.
There is no Game Creator → Dialogue for me.
I can create Dialogues. They are under Game Creator → Other → Dialogue.
But there are no Actors.
I have an found an Actor Script under Assets/Plugins/GameCreator/Dialogue/Mono/Actors/Actor.cs
I use the latest version of Dialogues 1.0.3
Customer support service by UserEcho