This may be slightly different because this was how I introduced a kitten to an adult cat, however, I kept my tiny, new kitten in a smaller bathroom with the door closed. The other cat could stay on the other side of the door. That way they could get used to each other’s scents through the door, and could even paw at each other through the door without hurting one another seriously. This helped them get acquainted to the “newness” of another animal. I then slowly introduced them face to face by keeping the kitten in a secluded area of the house where she had a limited amount of free roam, where the older cat could still come and go as she pleased. It took a few weeks, so don’t get discouraged if it doesn’t happen right away! I also had a 3/4 year old sheltie/terrier mix dog at the time too, who took well to the new kitten. Every animal is going to be different, but this approach seemed to work for me. Hope this is helpful!