What’s it like to write a novel? Much has been said about it, perhaps too much, but let me add one more metaphor anyway:
It’s like digging a big hole. By hand. You likely start out choosing where to dig and knowing the approximate size of the final hole — that is, you’ve chosen the genre and you know the final manuscript should be the size of a book. You may have carefully researched the site, taken copious notes, and done your best to be prepared. Or maybe you’re just going see what you find. In either case, you start digging, one handful of dirt at a time. The project is big and goes on for a long while.
If you’re lucky or did some test digs, you won’t find an enormous rock in the middle of the dirt you need to excavate. You will certainly find smaller rocks, tree roots, some worms and other critters — and bits of archeological ruins because we always encounter the past.
You’ll also find buried treasure, maybe a lot of treasure. That’s your best clue that you’re digging in the right place.