Hi, welcome to the forum.
. Tuti is lovely, but I’d advise against breeding her. You could lose her, meaning you have to hand raise her pups. You could lose the pups. You could lose both her and the pups. You may have to take her in for an emergency caesarean, which will cost thousands of dollars - and walk away without Tuti or her pups because the vet was unable to save them.
Plus, each season a bitch has runs the risk of pyometra - a potentially fatal uterus infection, and the longer a bitch is kept intact, the greater the risk of mammary tumours, which may or may not be benign.
If you still wish to go ahead, you’ll need to have her health tested (not checked - tested l, which involves blood tests and x-rays - not simply a vet running a hand over her, checking her heart, lungs and reproductive organs) for the preventable genetic disease which affect both the rottie and the schnauzer - what they are, I don’t know offhand, and I’m on my phone, so would have to leave this page to find out. You’d have to find a male who has had the same tests done, too, and one who compliments her in some way - this means he excels where she perhaps isn’t so great.
You’ll also need to have her temperament tested. Anxious or aggressive dogs shouldn’t be bred from, because temperament is s”hereditary.
Responsible breeders also have their breeding stock judged in some way - the show ring is a classic example, but you could also compete in working trials or obedience, for example.
They also guarantee - and stipulate - that if the owner of any one of their puppies cannot, for whatever reason, keep the puppy, they will take the puppy back - at any stage of its life, to prevent their puppies ending up in shelter.
Finally, they breed to better the breed. They don’t breed just because they want a puppy from their dog, or want their kids to “experience the miracle of birth, or they think their bitch “deserves to experience the joys of motherhood” (dogs really don’t think like that. Neither of my bitches have been bred - at least, not since they’ve been with me - and they don’t spend their time looking out of the window, daydreaming about the pitter patter of tiny paws that they’ve produced with the love of their life
). They do it to produce fitter, healthier, temperamentally stabler dogs than their own dogs.
They vet the families hoping for a puppy carefully - and don’t just hand over a pup to the first one at the door, willing to pay the asking price (which, by the way, may or may not cover the cost of the pregnancy, birth and raising of the litter. It’s not uncommon for ethical breeders to make a loss, or just about break even), and the best of them start early puppy socialisation and training before the puppies leave for their new homes. They don’t usually need to advertise, because they have long waiting lists before the puppies are even born.
Anyone not doing at least the vast majority of these, (and sadly, that’s the vast majority of breeders) is a backyard breeder or puppy farmer, who are unnecessarily risking the lives of their dams and puppies for selfish, usually financial - gain. Please don’t join them.