It's not anything like that simple.
Terry Pratchett described the organic process like
Now, I head down into the valley too. But I do with a spray can in hand and blaze the trees along the way. Make sure there really is a path I can make across the valley after one too many times finding my story petering out in the swamps and mud.
I certainly don't sit down and plan a book out before I write it. There's a phrase I use called "The Valley Full of Clouds." Writing a novel is as if you are going off on a journey across a valley. The valley is full of mist, but you can see the top of a tree here and the top of another tree over there. And with any luck you can see the other side of the valley. But you cannot see down into the mist. Nevertheless, you head for the first tree.
To be sure, when I go back and built a nice sturdy path, sometimes I find that I overerestimated the footing at a place and have to reroute, or at least go in for some heavy duty architecture to give it strength enough. And I continually have to jog the path to take in that little hollow filled with lovely bluebells, or send out a sidepath to take in the waterfall -- I don't notice everything while outlining, just the main plot. Still, knowing it goes somewhere definite is a help.