Vets like this really p*ss me off. They may know the veterinary stuff, but how many vets have ever actually bred a litter of puppies? You must keep the father away for a few weeks at least, otherwise the mum could feel threatened and may even desert or kill the pups.
Put the pen in a darkened enclosed area where she feels secure, in a sort of den, which is what she would do if in the wild. Do not let all and sundry (dogs or people) in to see them until they at least have their eyes open. You can handle them if the mum is happy about it (I had one who would have had your hand off if you touched her babies).
Heat is most important, provided they can get away from the source if they get too hot. If they are lying on top of each other then they are not warm enough, if they are sprawled about the whelping box then they are too hot. Try to find the balance, they should be lying near each other and making a sound like a load of bumble bees when feeding! Start to offer food at about three weeks - but be warned, once you start to feed the mum will stop cleaning up after them. Not sure which link I put on that kita has mentioned, I will go look and see if I can find any more.