Having worked in the veterinary profession most of my adult life. We find that the same questions keep on coming back. And everytime a new family starts with a new puppy they encounter the same problems most of the time.
This is why we recommend that you go and see your vet as soon as possible after you get your new puppy.
The veterinary technicians or nurses can help you with most of your questions.
The vet can check your puppy and although I have recommended several times that people take a puppy back to the breeder due to birthdefects I have yet to see anybody taken one back. So now I say that they need to be informed of what life will look like with a puppy with a problem.
If at all possible buy a puppy with an insurance policy already in place. That will give you some peace of mind. If not most of the time you can get 4 weeks free insurance at your vet ( UK and Australia) With petplan.
good luck with your new puppy.