Most of the time the vet will know exactly what to check These are some of the things he should check but almost always are fine so don't worry.....When I bring my puppies he checks everything from the top down to the toes. Always check tail for tightness, inside the mouth to rule out a soft palate. Check Nares (nostrils), and listen real well to the heart for any heart murmurs. He will also check the eyes for any entropian which could cause the lids to turn in and cause the eyes to water. He will check the Vulva to make sure it is not turned in which could cause urinary tract infections....Good luck at the vet tomorrow and most of all have fun with your new puppy!