Kittens will find the litter box. They migrate to a substance or surface which is suitable. As the interior of a human home has no such surface the litter box stands out for them. It is prominently the correct place to go to the toilet. And after they have used it for the first time it will smell of them and their pee and poop and so it will become even more obviously the right place to go to the toilet. That’s it. Just make sure the litter box is in a private but easily accessible place and all should be well. You may need to try different makes of litter but a kitten shouldn’t be fussy. Don’t declaw your kitten as she won’t use the litter tray and worse, much worse will befall you in your relationship with your kitten.