Again, the advice you are getting on emergency care of kittens is great... but do not panic about all the things that could go wrong. Most cats have healthy kittens without much trouble.

Be aware and prepared, but in most cases, the female does just fine. Good food (whether special food or just as much of her regular food as she wants to eat), a safe warm place to keep her kittens and plenty of fresh water and she will most likely do fine. Putting old clean towels in her nest box is a good way of giving her a soft warm bed that is easy to wash, but if that's not an option newspaper is a good insulater (warm) and can be thrown away when dirty.

Some cats become very protective of their babies, so if she gets hissy don't take it personally or worry. Some cats love to have their person admire their kittens. Watch your cat to see what makes her comfortable. (One of my females back inthe day used to come in the house for treats and cuddles between giving birth to kittens... that was very unusual. Moms don't usually eat while they are in labor, but Sootie was hand raised from two days old (her mom was killed by a car) and she was a very devoted mommy cat.)