Elaine is right on with both the amount of traing and type, as well as the exercise thing. I personally only 'train' puppies so young by making everything a big fun game so my puppy can't wait to listen and learn new things. So treats/toys/play mixed in the bunch makes for a well trained and enthusiatic older dog.It all depends on your puppy. You can incorporate minor training in your everyday life but the real training depends on your puppy's attention span and ability to focus. I did twice a day training for 5-10 minutes every day at 8 weeks but my dog is a high drive dog. A lower drive dog you might get in 1-2 minutes twice a day and that's all you are going to get.
The amount of exercise also depends on your puppy. You can walk your puppy as much as you want so long as you don't push them to go farther or faster than they are willing to go. Chances are around the block is about as far as a puppy this age is going to be able to do.