Your cat will have been through a lot the day of its adoption. Although all you may want to do is hug it and play with it, at the moment, both will be near impossible. Your kitten has been moved to foreign turf, and knows nothing of its surrounding areas, or you, the good-intentioned person trying to shower it in love. For the first day or two, you need to be aware of this, and give your cat time to adapt. This entails just sitting still and smiling and seeing if the cat wishes to come towards you. No matter its reaction here, eventually you two will be as thick as thieves, it just takes time.
Cats are territorial and like an area to call their own. When they come to their new home, I would advise you to set up a small area, possibly a bathroom, packed with cat amenities (food, water, their litter box, toys etc.), to create a comfortable space. The litter tray should have 1-2 inches of litter and be in a place that it can be used privately. Your kittens feeding station should be away from this.
One of your new cat’s favourite things to do will be to survey its territory. I think that a cat tree is the perfect way to do this. They will be able to suss it out and make themselves comfortable with it far quicker than they could at ground level. The cat tree will also serve as a scratching post, and allow your kitten to make their nails less sharp.
Your cat won’t need to stay inside forever, after a few weeks, once big enough, they can move into their own little cat house and have their own little safe haven to call their own.