Well first up-it has to be puppy food (large breed puppy food is better still).
And amount I can't help you with. We've always free fed-so left a big heeping bowl of food for the dog to eat when and how he feels he should. You might be able to do this. Personally I feel it's easiest in terms of no measuring no worrying, and no gobbling food up like theres no tomorrow.
Drawbacks -getting fat (not as a puppy, chubby puppy is fine), mulitple dogs, and potty training (it's easier to have planned meals and planned potty times.
So I'm not much help on amount. You MUST give three meals a day to a puppy, you can cut to one or two with a dog but they must have three while growing. And amount should be indicated on the dog food bag.
Have you figured what brand of dog food you are going to feed? Might I suggest Orjien