“First, Create a World,” he said.
You don’t have to invent whole languages of Middle Earth, or spend 8 years researching before typing your first word as Eco does. But know your world, how does your novel greatly or subtly differ from the history of our blue planet? This should be fun. Don’t be perfectt.
And when you start writing, you don’t have to impress the readers by telling them all about the world. It’s enough that you know. Tell them a little by little as it fits.
Now, if you are one of the 537 literate people in the world who never read J. K. Rowling’s Harry Potter and The Sorcerer’s Stone, read it. Or reread it. This is a great example of how to unwrap your world a layer at a time. You are giving them a beautiful present of your story world, let them enjoy unwrapping it with delight.