I read essentially the same thing in On Writing, By Stephen King.
You start with an idea, a story, a character, etc.
And you add to it as it comes to you.
Write a paragraph: And then what happened?
Another paragraph: And then what happened?
Afterward, it can be a blur.
Did I write that?
This is especially true the pieces you are most proud of.
Don’t act like you don’t go back and re-read them too.
Very few writers really know what they are doing until they’ve done it.
–Anne Lamott, Bird By Bird