Check with your local library to find out if there are any writers conferences in the area. While you are doing all this, write down in a notebook or on a computer any ideas that come to you about the book you want to write. Setting, characters, situations. Develop those characters, research the setting, develop the situations. A novel starts with a small thing and you have to just add to that small thing until you have enough to base a book on.
Some writers say they just sit down and write.
I gather material until I have enough to base a book on, then I do a synopsis. Then I write the novel. I hope you will take this one step at a time. Too many people think you can just sit down and write a novel. None of us would think we could pick up a violin and play it right away without some instruction, or some practice.