[windsonguk]

Most breeders don't mate their bitches until the age of two years plus.
Prior to any mating at the very least, it is sensible to obtain hip and elbow scores on the Sire & Dam, and health checks such as heart/ eye etc - two wrongs never make a right!
Do you have the history of the generations behind them HD/ED & health screens, ensuring the match is correct = forward planning.
I would seek local advise asap, multiple matings are not advised and can cause serious complications later in the pregnancy and birth.
Get the ' Book of the bitch ' and read it fast. It gives a vast amount of imformation
needed to produce a litter of puppies.
I would advise you go see your vet asap they will also be able to give advise on scans, nutrition and care for the Dam and pups thereafter.
But more than anything find some one local to you with experience of rearing puppies. without the information you could loose Dam and pups.