Firstly you need all the scenes you want for your game in the Unity build settings. Then you need to call the Engine: Change scene action. The input should be the number that you have for the scene in the build settings.
A sidenote with that: take care when updating Adventure Creator to not overwrite your build settings with the one that comes with AC (like I did once) or you will have to add all the scenes again You can find the Build settings under the File menu. Just drag all your scenes in there and reorder to taste.
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