It’s wonderful that you took her in though, good luck with the new family

just hold your old cat so that it knows it's loved and let them meet and then they will chase each other around for a few days and the new cat will hide under whatever and in a few days, they'll take naps together.

Good luck. You have a new distraction!

I think you nailed it. My only hope is my cat can chill with it eventually! She needs a buddy.

because my older cat was bored and chasing his own tail. It's so hilarious to see the big cat running with a train of 2 little cats right on his tail! He acted like he hated them for a couple of days, but now he runs around with them and is teaching them the art of the kill. Mice, voles and moles have no chance here!

In the past, I've made a screen door insert for a bedroom door to allow cats to become acquainted face to face while still keeping them separated for a few more days. It only require a wooden frame, some bug screen, and a hook and eye to hold it in place. Chicken wire or a piece of mesh fencing works, too.

to the door frame with velcro. It was only supposed to be a temporary solution and it worked very well. When my sister moved in with her 3 cats, we got a handy person to install a Home Depot wooden screen door and that has been a real help in keeping the younger cats from bothering the old ones. The screen door is mounted to the door frame so the bedroom door still opens and closes as it should.

Let them sniff each other through the screen for a while. Repeat in stages if they don't get along right away.

It mimics the aroma of the hormones that mama cats smell like -- something familiar to felines.
It comes in a plug-in and also in an aerosol spray.

It is widely recommended for multi-cat sensitivities. Available on amazon, and at many retailers and pet stores.

There is another product called Rescue Remedy, an herbal mix and it comes as a tincture -- you put a couple of drops in their water or food. Also widely used for calming. Also available on amazon and at pet stores.