I would first write everything i could think of about the planet where the fiction takes place, landscapes and lifeforms. Then describe the society that lives there, who they are, what they are, what they believe. Then try to list everything I think is important about the place, trying to get as much descriptive imagery out onto the screen as I can. Then I would wonder about what would be helpful to people living there, what tools and societal norms would be beneficial.
Once I had a LOT of detail written down I would start to further develop each facet of the world with ChatGPT, deciding what I can about each scale I look at the world in. I would keep all the useful information in a text file and organize it into a ‘world bible’. Then I would feed this into a custom GPT to contain the knowledge of the world so that I can explore it further.
Afterwards I would decide what kind of format would be best used to share this world with other people. Pictures, stories, travel guides, national geographics? Would there be a unique language or alphabet that would need to be made like Tolkien or left ambiguous like the Seraphinianus?
I would like to discover novel societal solutions to living in a fictive world and what sorts of moral dilemmas or ambiguities could be found within.