That heading boils it down nicely, but maybe a little too far. Writers, one and all, can be placed on a spectrum. At one end are the pure improvisers; as Lewis Carroll said, they "begin at the beginning, go on to the end, and then stop". At the other end are the pure planners; they start with a sentence, expand it into an outline, and so on into a draft. Most of us are somewhere in between, and for some writers their position on the spectrum isn't a big deal. Myself, I'm mostly an improviser and as a result, my advice is of little use to people near the planner end of the spectrum.
People in the middle I have the least understanding of, so if that's where you find yourself, then you'll have to decide for yourself how relevant this is to you. Do you take advice from both sides, pairing mine with a planner's to get the right picture for you? Or are neither of us relevant to you?
Wherever you find yourself, on this spectrum or any more relevant to you, you'll find that approach to be both where you do your best work, and where you have the easiest time getting any work done. To quote a writer far better than myself:
"This above all: to thine own self be true"
There is one big prerequisite to beginning a novel: You must /feel like/ beginning a novel. If you're writing for the money, then you're in the wrong industry the money here is nothing but a tall tale, exciting to read about but never appearing in reality. Instead, I assume you're in this because you have stories inside you trying to get out. Getting them out is not a trivial task, and that's what I'm here to help with. When you don't have a story inside you're trying to get out, it's not time to start a novel. You can continue work on a previous one, but not start one. If you're not the kind of person who has stories inside you trying to get out then this book, and likely this industry, are not for you.
As an improviser, there are three beginning methods I find useful. I present them from most-improvisational to least-improvisational; if you find yourself thinking "I'm not *that* much of an improviser" while reading one, then skip to the next method.
Those writing in another language may note that the Fractal Method relies upon English putting the subject of a sentence first, and to some extent upon English obsessing about verbs. In a language that differs in those ways, the Fractal Method lacks the "punch" it has English. For such a language, I recommend constructing the sentence in this sequence, even if you're jumping around the sentence to fill it out and on your second draft, rewriting this sentence entirely, so that its replacement flows naturally.
The "big picture" for this method is that a beginning, when considered at one size, is a microcosm of the next larger size with the largest size being the novel itself. (Although once you've gotten the first one down, you can continue this method into a trilogy and beyond.) You have the name not just *a* name, but *the* name then a sentence fragment composed of the name and a typical action, then the first sentence, then the first paragraph, then the first page, then the first chapter, then the novel as a whole.
There are a variety of things a story can be "about"(see the Arcs chapter for more on this), but in one sense, stories are about a character, and that character's actions. That character is how you begin. Start with their name not their full name, but how you intend to refer to them for the rest of the novel. Usually a nickname, something their most intimate friends might call them, something they call themself. By the end of the novel, your readers will know this character intimately, and this is how two readers who just finished your novel will refer to this character when talking about it. Also, on a more-prosaic note, the reader of this text needs a textual hook where they can hang everything you tell them about a character, and the Fractal Method gives them that hook front-and-center.