My first cat Grisette had a litter two times. They look for a safe place and you can even notice the time has come when she starts to search. Grisette first time found that place in a closet. When we opened the door in the morning, there she was with her 4 purrfect babies on a stack of old clothes that was on the bottom and she had it all cleaned up nicely and was very proud. So you see that when all goes fine there is really nothing you have to do.
The second time (which was unplanned- at that time back in 1977 we thought she should have kittens one time but she became pregnant after the first birth in no time. I didn't have the heart to have them aborted and found good homes for all of them- including a litter I found abandoned in the woods at the same time) she accepted the nice box with towels we had made for her behind a paravent and I could watch it all. It was one of the most touching experiences of my life and it all went well. She licked herself while the little kits hatched enclosed in their coat of slime and licked it all away until they looked like wet little mice and then more until they showed they were furry
I will never again have a cat getting pregnant but I wish I could be part of that experience again