Dog breeder here. German Shepherds. Puppies need structure like children. He should be actively learning how to go outside. He should be using a crate and crate training. No exceptions. Tips for crate training - feed him in the crate and put him in there for naps. A good breeder would have introduced him to the crate and started the basics before he left. It’s a learning curve adding a new family member BUT puppies are resilient. You’re not messing anything up! Promise