How do you introduce a 6YO cat to a 5 month old puppy?

Why do you separate them? If they get used to each other, it's no problem. I brought kittens, on several occasions, into my house with an older yorkie. The last kitten I brought in last summer go along so well with my yorkie puppy that they slept together. Wish I could email you the pic with them lying together with his arm around her and just the opposite a few months later when she was twice his size. Unfortunately, she died of FIP at the end of February at 8 months. I was blessed to have her for 6 of those months.