I'm a cat owner but my cat is an indoor cat. I dont have a problem with outdoor cats, its just that i would be crushed if anything happened to my cat prematurely thus I always keep him inside.
Similar to most of the other girls, I'd say that there is no training to make them indoor/outdoor, but that they know there home and have a sense of how to get back there.
My cat had NEVER been outside for 2 years of his life when my roommate accidently left our screen door open over night. He was gone for 2 days and somehow found his way back to our place even though we lived in a massive apartment complex where all the buildings look the same!
enjoy your new kitten