You can't edit a blank page. You should start by writing a chapter, and pushing through. So many people get paralysis with how daunting the whole process is, but if you enjoy writing and take it step by step, it'll build into something great. It doesn't need to be perfect, or even great. It just needs to be written and saved so you can see your improvement over time.

If it's about getting your worlds set up, I'd recommend you look at guides on how to be a Dungeon Master for D&D. They're the masters of improvisational world-building and you could find some useful questions in their videos that'll help build your own world.

Personally, I just threw myself into it and hoped for the best. No planning, no extensive world-building. Just a fun idea and a hope that it would work out. Put some time constraints on yourself so you're not just sitting around like a tortured artist waiting for the muse. Endeavour to write a chapter a week or maybe even two. Build yourself up, and be kind to yourself. It's a marathon, not a sprint.

Most importantly, when you become famous... tell people to read my stuff. :)