I have found that leaving them to their own devices tends to work well. The new kitten will be getting used to its new surroundings and it takes time for it to settle. A friend lodged with me for a while and brought her 12 week old bengal kitten with her. He HATED my cats for at least 3 days..... then all of a sudden all was well and they even shared beds and cleaned each other.
Best not to force them into anything. They will make friend when they are ready usually.
Though i have to say ..... i am no expert by any means and im sure others on here will have great advice too

Good luck!

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