how do i introduce my cat to new kittens?

[Pinkie]

I will be getting 3 new kittens soon, 2 are for my family, one for my mom and one for my aunt, but i am going to get them from a friend and my moms going to come get them from me when she has a break from work, and i have a break from school....
but the problem here is that i already have a kitten... he'll be 4 months on the 15th and they will be 6-7 weeks old. he's not very good with other animals just on a daily basis of introduction. he's going to have to get used to having a little sister, but i want them to get along, i dont want him hissing at her, or the other kittens that will only be here temporarily, and making them evil kittens......
whats the best way to introduce them, so they'll be used to eachother and get along???
oh and the kittens will be getting dewormed and i'm worried the worms they have will get passed to my cat..... should i be worried about this or will they be fine??

 

[pura_rosa]

Slowly, eventually they'll be friends but don't push it, just give them time.