Writers are often asked about where their ideas come from. For me, that would be lightning strikes of creativity where my brain concatenates events and experience with my imaginative wanderings.
Ideas are a popular focus for questions, but I don’t think I’ve ever heard anyone ask where the details of the story develop. This is just as fascinating to me. The details of a story are the building blocks for the tale. They’re the rich loamy soil where creativity can take root and flourish.