Exercise

Keep play sessions and walks short. You could take him places that you know are safe (as in, rarely frequented by other dogs - or to a place that you know the dogs are well cared for and up on vaccinations), and carry him around at first just so that he has some exposure to the real world. For example, when I had a little pup, I took him to our SchH club, since I knew that all the member and their dogs, but did not take him out to pet stores of public places until he was older and had at least a couple rounds of shots.

For the first few days, play it by ear as to how much to do. If pup is stressed and wants to sleep, let him. If pup is hyper and wants to play, take him out and play. He probably won't want to have anything to do with leash walks at first, so get him used to dragging a light leash around, and get him used to being walked around a bit in the yard with you holding the leash.

By the time he is 3 - 4 months old, he should be able to do 20 to 30 minute leash walks without any problem, other than getting bored (bring treats, a tug toy to play along the way). Though he should be able to do nice long walks/hikes off leash on soft surfaces, running and walking at his own pace.

WHat do you plan on doing with your pup long term?

People have a habit of doing way too much with a young dog b/c of their own personal expectations of the dog. Take your time and let him get comfortable.

Most trainers will say not too much strong obedience until they are around 4-5 months ..some say 6. Just work on sit, down, stay, etc. You want to spend your time working on the 2 most important things......1) getting your dog to focus on you. 2) Recall.

Recall is the most important thing to work on. Starting early is the best.
I have right now 95% recall. I took him to petsmart to get a bath and the leash slipped out my hand and ran to people giving him attention. I told him to come to me. The first time he looked at me and the second time he ran directly to me. (he is 10 weeks). Not bad for his first contact with the outside world. He wont have anymore until he gets all of his shots. He just needed a bath though!! lol. $16 for a puppy treatment with oatmeal is very affordable.

after my dog had his 2nd round
of shots we were out but with caution.
we also waited a week after he had his 2nd round
of shots before venturing out to far. i didn't go
to pet stores untill he was 6 months old or so.
invited family, friends and neighbors to visit
us all of the time. i also had people visit with
their dogs and pups.

as far as training i didn't really do
any formal training untill my dog was 4 months old.
before 4 months he knew his name, come, house broken
(within 10 days), crated trained and not much more.