Hi and Welcome to Pet Talk.

Congratulations on your new addition to the family.

Catnapper has given you some good advice and I would like to add a little of it myself.

Having to introduce two kittens in the past to my older ones, I found that after the separation period, I would hold the kitten on my arm in a straddled position and let the others smell the butt end first as this is what they normally do. I would do this for a few days and then let them smell the face for a few days. Then under supervision, I would let the other cats come into the room where the kitten has been. I would do this for another few days,
then I would just leave the door open and hoped for the best. Fortunately, everything went well for me and I pray that it does for you also.

Please keep us updated and do not hesitate to ask any questions as we have quite a few of experienced rescue workers here on board.