When your puppy is younger than 5 months of age, it's best if you can feed him 3 times a day. If you cannot due to your work schedule, two meals will be fine.

Decide approximately what time he will be fed and stick to the schedule as much as possible. Again, this is to aid in your housetraining efforts.   Once you know your dog is housetrained, you can move to feeding two times a day or you can stick to three.  There is no set rule.

Some people do something called free-feeding.  This means that a bowl of food is put out in the morning and throughout the day the dog eats whenever he feels hungry.  Although there is nothing that says this is a bad idea, it's not been something I've ever done, especially with multiple dogs in the home.  

This may work for some people who have pickier dogs, but that's never been my dogs!  I've always had dogs that love their food and eat it all.

For success in housetraining a new puppy, give him 5 to 10 minutes to eat.   Whatever he doesn't finish, be sure and pick the food up.  You can either put it in the fridge for later or if not much is left, throw it away.   Why?   If he isn't housetrained yet, you are trying to put his body on a schedule.   

Use your feeding times as a great way to instill good training.  While your pup is waiting for food, ask him for a "sit", or a "down".  How about a "leave it".  It's always good to find ways to have your dog "work for a living".  This builds a great relationship!