A new cat entering your home needs to have a room to herself where she can mentally and physically adjust to her new environment (smell, noise, people, surrounding).
Change is threatening and stressful for cats, so giving your new cat a “safe room” is a kind and thoughtful way to help her transition into your family.
Regardless, if you provide a separate room (like e.g. a guest room) or a bathroom, the place should:
Place in this room (even if it is only the bathroom) following items:
Don’t bother with expensive cat beds at this stage. The easiest and most comfortable for your kitty is to leave the cat carrier in the safe room. Take out the door grid and place a comfortable blanket inside. If possible, place it in a hidden corner or – if possible at all -
If you want to help her calm down, use FELIWAY (synthetic version of feline facial pheromones) or Catnip (a herb called Nepeta cataria, a relative of oregano and spearmint). It makes objects seem familiar to your kitty, which is very reassuring and calming for her.
Spraying the corners and legs of furniture makes the room less alien and more inviting to her. Both can’t be detected by our nose (means, they don’t smell to us).