Bringing Home a New Cat or Kitten

Prepare a safe room.

A safe starter room or sanctuary for the new cat will provide the cat with the quiet and safety s/he needs while becoming familiar with the scents and sounds of your home. The starter room can be any size but must have a secure door and ceiling.

Cat-proof the safe room.

Check out Cat Safety Tips and Escape Prevention sheet for more information.

Give kitty a place to hide. New cats are often nervous and like to hide. Cardboard boxes or sheets draped over chairs make ideal hiding spots when you first bring kitty home. If you’ve adopted a shy cat, we recommend removing large items of furniture from the room, such as beds and dressers. It is much easier to interact with a cat hiding in a box than a cat hiding under a bed.
Help your new cat get to know you. Place a t-shirt or a piece of your clothing that contains your scent in the safe room.
Equip the safe room with cat food, water and litter. Place food and water on one side of the room and an open (unenclosed) litter box on the other side. Shyer cats may not eat much during the first 24 to 48 hours and may experience temporary diarrhea from stress. If your cat has not eaten in 48 hours, try some extra tasty treats such as canned tuna or salmon. If this is not successful, you may want to consult your veterinarian for advice.
Give your new cat a new post. Put a new scratching post (at least one metre tall) inside the safe room. Scratching is a natural and comforting behaviour for cats. It’s also important that the scratching post is new and has not been used by other cats. Your new cat does not want to be stressed by the smells of other cats while s/he is first adapting to his or her new surroundings.
Feliway saves the day. If your new cat is an adult, you can use a store-bought product called Feliway. Feliway imitates natural cat pheromones and helps a new cat feel more comfortable. Feliway comes in a spray and diffuser form.

Give your cat some cat toys for entertainment. Provide toys such as mice and balls in the safe room for when you are not around.
Spend time with your new cat. In the beginning, visit frequently for short periods of time. Visiting can mean interacting directly with the new cat in the form of play or petting, or quietly reading a book or chatting on the telephone in the same space as your new companion. Keep in mind that a nervous cat may growl, hiss, twitch its tails or pull its ears back. The best response is to speak softly followed by giving the cat some time alone.

Transition beyond the safe room. When you and your new cat have established a trusting relationship, the cat is ready to begin exploring the house. Be sure to begin this process when you are home to supervise. Close most of the doors so the cat begins its orientation in stages. Too many new spaces at once can be stressful and frightening. If you’ve adopted a shy cat, be sure not let it in the basement for many weeks. Most basements have many hiding places—some inaccessible to humans.
Ready to explore the roost. Remember, integration into the rest of the house is dependent on the personality of your new cat (as well as your existing pets). Sometimes the integration process can begin in just two to four days; however, sometimes it is best to wait a couple weeks. Shy cats in particular may need a longer integration period.

Original https://www.meowfoundation.com/resources/new-cat/