The dog is still very young and new to the environment. Expectations should be kept low and training should be fun and easy for the next few weeks.
Spend as much time as possible outside with him just hanging out, tossing a toy, running around, and light obedience. Rule #1 for puppies - a good puppy is a tired puppy. This rule is in effect for biting, jumping, and every other puppy problem. They need both mental and physical work on a daily basis otherwise they get bored and that can lead to neurotic and destructive behaviours
GSD's are bred to herd and be a partner to the shepherd, that means they genetically want to be with their human 24/7 and being separated can be very hard. Their nickname of 'Velcro dog' is well earned, normally that means they can follow you around the house as you're cooking, cleaning, doing laundry, etc. but being outside negates those options so you'll need to work harder at building that bond and avoiding separation anxiety.
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - Male GSD - born Jan 26, 2012
Koda & Zazu - 5 year old male cats
Alex - Male Cocker Spaniel (rescue) - RIP Cuddlebug 2007-2010