My first 3 weeks were focused on bonding, socialization (in yard until shots were done), potty training and watching poop (to make sure her food was digesting well) and play! of course. You will become a poop pro! Biting is for toys not hands or feet (ouch!) Don't let a bad biting habit get started - it can take months to reverse and you will regret it.
The GSD's I've had the pleasure to own through the years all liked routine. I think establishing routines is important - feedings, potty breaks, exploring, play times, nap times etc.
Puppy proof everything. Put away everything they can reach that could harm them if it is eaten or bitten. Conceal and block off all areas with electrical cords.
Take tons of pictures! For the first 8 months taking pictures can be a challenge - they move so much
Store the keepers and discard the blurry ones
. Start a monthly height and weight chart. Keep it thru the 1st year or so.
One more thing... some new owners get in a hurry for training. Your puppy is a baby and the first few weeks they are overloaded just learning the new sights, smells, textures and tastes of our world. They have very short attention spans, so don't get frustrated. Enjoy!