My writing process is not always uniform. Sometimes I start with an idea that I have over what the paper should look like and then just go thru all the main points. Then I come back and work on the details, expanding some of the short arguments and then the refining process begins. Review, correct, review again and make more corrections and the final paper arrives.
That is one process.

And other times, I start with an outline. What should be my title, and how should the intro be, the ideas in it. Then the body of the paper, and the conclusion, etc. Then the expanding process begins.

And sometimes, I start from the body of the paper and then work on the intro and conclusion.