Think of your novel as a gold mine, with a mother lode resting deep in the heart of a mountain. In order to get to that treasure, you have to build a sturdy framework as you dig into all that dirt and rock. You don’t want the mine to collapse on your head—that would spell disaster.
Now think about the entrance to the mine, which is particularly important to attend to. All the bracing and construction that follows will be built off that initial structure. So if it’s flawed or built with flimsy materials . . . well, we’re back to disaster.