What do you mean by exercise? Do you mean walks? do you mean running around playing and chasing in the backyard? Do you mean retrieving a ball? Do you mean playing tug?
These are all forms of exercise. Start with short walks on leash...5 minutes ,two or three times per day...and add time as the puppy get's older and stronger.
Free play...should be as long as the pup wants to play...they tucker out quickly and just lay down when they've had enough.
Gina