The introduction part should take a few days. First allow a small room for the kitten. A litter box should be placed on the opposite site to the food and water. As he/she gets comfortable with the small room, he/she will be ready to explore other places and retrieve to the small room for safety. Feliway, a natural product made of cat pheromones, can be used to speed the process and decrease the stress associated to the new changes.
For more info on how to introduce a cat into a household, please check out the link. There are many other good sources to learn about how to provide care to your cats. Some good information can be gained from the American Association of Feline Practioners under the cat health topics.