Introducing new kitten to other cats

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I have just got a new cat. Shes 8 weeks old and so far so good. Eating,drinking and using her litter tray. My older 10 year old cat is totally fine and not bothered by her. My 4 year old cat keeps hissing and growling at her and I am supervising any contact between them and hope in time the 4 year old cat will adjust. They are all females and my older 2 are spayed and new kitten will be done when she can be done.
Any advice please with the 4 year old with the kitten. I know it's not a guarantee they will bond but want to make it as comfortable as possible. I am praising the 4 year old and playing with her as usual.

We had two kittens, then after a couple of months ended up with their mother. Initially it did not go well, to the point we were thinking of giving the mother cat away. However it just happened that we were going on holiday so we set it up that during the day the kittens were in the lounge and kitchen and the mother was in the office. Then my family came round to visit in the evening and spend time with them all in the lounge. Then the kittens were in the kitchen over night and the mother had the lounge and office. In the morning my family would again visit and spend time with all of them before putting the mother back in the office and the kittens in the kitchen and lounge. We were away for 10 days and when we returned the mother and kittens were friends!!!! It was amazing!!