I am vibe coding an app for personal use (todo app). Once happy with UX I intend to write much of it the old way. But I want to figure out what I am building fi

I am vibe coding an app for personal use (todo app). Once happy with UX I intend to write much of it the old way. But I want to figure out what I am building first. I feel like it is like using Excel before building the real thing.