Shih Tzus

Hello fellow animal lovers,
My 14 month old shih tzu is due around the 10th of Aug. This is her first litter and she is getting sooo big. I am in close contact with my vet to make sure everything is going good. We will be having her ultrasound done the first of next week, at 47 days prego. She is so beautiful and I am so worried about her. The vet says she is doing great! It is so cute to see her little stud/daddy
taking care of her and always licking her and snuggling.
Anyway, I only want to breed her once. If all goes well, I will have her(Roxy) and my little guy(Bo) neutered afterwards. I would really like to get some advice on what to do to help her deliver as smooth as possible. I have been reading everyones comments and I have read countless books about my part of the delivery. What is the best thing to use and what do I do to get her whelping box ready? Do I need to help the pups out of the sac? Do I put them at her belly as soon as they are cleaned up or do I wait til they are all out before I lay them down? What do I do with the placenta? I have read that she should eat that for the extra nutrients? I also heard mothers will eat the poop to keep the box clean, should I let her do that or get rid of it before she gets it? I would appreciate any advice to help my little granddogs and their mom go through delivery safe and healthy.
Thank you for any help,
Almost a shih tzu grammy

Why did you breed her so young? Do you have a mentor? Is she a show dog? How old is the male? When it is time for her to deliver she should not be anywhere around the male,it will stress her out.Has your male been checked for herpes?