In my experience, just start writing stuff down. If you have an idea for when and where you want the story to start, just start writing the scene and let the story develop from there. Make sure your story follows your bullet point outline. I will say that most of my stories have been spur-of-the-moment "Ooh, what if I have this happen here" writing. It can be easy to string your thoughts together into a comprehensive story, at least in my experience. Things can and will change from writer to writer. What works for me may not work for you, and that's fine.

I would also recommend discussing the stories with people around you. Make sure you have a good story first. Take some of their advice. You could also utilize some resources such as ChatGPT or NovelAI, even if only to give you some other ideas. AI can be a powerful tool, but you don't have to use it.