Oh sorry I misread your question 😊 I didn't have much time so I think maybe 4 hours? It's difficult to say. I wrote some starting ideas, but as English isn't my native language, I let chatgpt translate and expand on some content I didn't have the right words for. The way it writes isn't super interesting but it was fun to play with it as a raw material. I'd say it writes not super interesting ideas with great wording 😁 It's a little bit difficult to explain but do you get the idea?
Also writing the text is one thing but designing the story structure is super important, so I used a graph for it.
I often do narrative games and it helps to know your endings earlier so that you can fill the steps to reach them.