A warm welcome To PT TXUKES. I'm sure you're going to love it here.
When my son moved back home with his cat,(Sades) I had to make an intro to my three cats plus the dog. After of few days of Sades being here, in my sons room, I put him in the cat carrier and brought him out to the living room and put him down on the floor. My three cautiously surrounded the carrier and of course there was some hissing and growling. I kept him there for about half an hour then put him back in the room. I did this for about a week and each day I would leave him out, but still in the carrier,
longer. Then by the end of the week, the door of the carrier was left open and out he came. Fortunately for me, it went fairly well.
Of course there was some hissing and growling, but that was about it.
I wish you the best of luck and hope to see some pictures of your furbabies.