nEW kitten in the household...how?

hey there..
i already have a 1-3mths old kitten. i have been keeping it for 2-3mths long. today i've found another cute kitten at Eunos. i dunno how to introduce them as when i tried, my kitten tried to fight with my new one.my new kitty is not as aggressive as mine.currently keeping the new kitty in a huge cage with my own kitty trying to get in the cage.i need advices on how to introduce them and stop my kitty from trying to fight with my new kitty.and approximately, how long will it take? thnks guys!!