It sounds as if you would be the most comfortable by outlining or mapping each vignette individually, using that map or outline as the framework for your prose. Once you do that you can hang the prose on code so the code acts as your skeletal structure.
This would allow you use your strength as a foundation throughout the entire project.
Edit: Here are a couple of essential links for beginners:
This is a master link to help you learn CS itself: Master Link for Beginners
This second link is a tool many of us use to make coding easier. CSIDE tool: CSIDE hub