The answer to this question — without meaning to sound snide — is to learn the craft of writing fiction.
Note that I said the craft, not the art, because they are two different things and — good news — a craft can be learned.
There are workshops, books, online courses, free information everywhere that will teach you the craft of writing fiction. The only difficult thing for you is to find the particular method that will work for you. That will suit both your personality and your method of writing.
So start looking and, when you find something that resonates, try it out. It may not be right for you but maybe the next thing you try will be perfect.
Then, and only then, you might want to consider how much art is involved in writing a story and you might also want to consider whether or not you wish to pursue becoming an artist as well as a crafts-person.
Personally, I believe that you can write excellent fiction either as an artist or as a crafts-person. Or both. It’s just a matter of preference.