Have lots of patience with him. Don't push things. Let him acclimate before you expect anything out of him. Don't try and introduce him to your whole family and all you friends right now. It will probably take a while for him to trust and bond with you, maybe even months. Two weeks is the general down time for a rescued/adopted GSD--don't try and make him do anything other than eat, sleep, poop and pee during that time.
Is he a house dog? Is he crate-trained? Have you owned dogs before?
Others on this forum will add lots of good information, you will probably see more posts tomorrow.