I fed the puppy three times a day when she was really little, then eased off to two times a day. Some people feed their dogs once a day, I guess, but that seems kinda cruel to me. I feed them in the morning and the evening. Read the label to figure how much the dog should get per day, and then divvy it up by the number of feedings.
Personally, after the Late Great Melamine Flap, I cook my dogs' food using guidelines for canine nutrition. Sane people, however, can use whatever dog food is most convenient. If at all possible, try to find one made in America with American ingredients. (Some manufacturers pull a fast one by claiming the stuff is made in America, when the ingredients come from China...the very source of the melamine contamination.) But in reality...it probably doesn't make much difference: just pick a high-quality premium brand. Your vet or breeder can suggest one.
Also be on the lookout for propylene glycol. It is used to make the food look nice and last longer. Problem is it is a kissing cousin to ethylene glycol (anti-freeze).