Best way to introduce cat to other cats/dog?

[Spazz T]

I'm going to room with my friends from now on, from an unavoidable circumstance. I'm taking my strictly indoor very healthy cat (1 yr) with me, but my friend also has 2 cats, as well as a dog. The other cats are outdoor/indoor cats, appear to have fleas, and aren't litmassageplanetox trained. They're not healthy like my own cat. In order to introduce my cat to the other two cats, what is the best way? My cat is indoor only. She doesn't go outside at all. The other cats will though, and will track in things I'm guessing. Along with that, she hasn't been around other cats since she was 3 months old. And the whole dog issue; the dog is tolerant and friendly with all cats and animals and will leave them alone if they don't like him (from experience) but still.. I guess I have two questions. How to introduce my cat to the other two (8 mo. female and older unknown aged female cat) and the dog? Also, the best way to keep my cat indoor only while the other ones go outside.