Getting 2 cats 2 get along :)

Getting 2 cats 2 get along :)

I have a female cat who is a four year old mongrel, and i recently (2 days ago) got a new male kitten who i nine weeks old from a RPCA center. Does anyone have any good tips on getting them used to each other. The eldest cat has A "friendly" cat that appears round m house. She doesnt mind this cat walking about in her territory and just sits back and watches him. Also sh has been in a cattery about 4 times while we went on holiday. Though so far when th older ca has been in contact with th kitten she just hisses (as expected). Any hlp appreciated. :).