How do you introduce a new kitty to two other cats?

okay make sure your new kitty is in a a seperate room like a bathroom would be best, give him everything he needs to live in there, since there is a crack in the door you should bring all your cats to the door so they can smell the kitten from under the door and then they will know there is a new kitty, do this about 3 times a dat with each cat and then when they get used to the smell open the door so they can all see what's inside do that about 3 times a day too, when they know what's in there try letting them be in there for about 1 min but don't let them hurt the kitten, do that a couple of times a day too, when they can stand to be in the same room as the kitten take a dishrag and rub all three of yout cats so the smell will get on the rag then go to your kitten and rub it on him so it will smell the same as them, do that every once in awhile, when they get used to him let thim play with the kitten for about 20 min then keep increasing the time of playing when you feel that you can trust your older cats let the kitten roam the house with his new buddies