Also remember- he may not be leashed trained.. He may have no clue what he is supposed to do with " this thing around my neck". However- since he doesnt know where he is, being off lead is out of the question. I noticed on the other post the suggestion of calling the breeder first. I agree- maybe they can tell you somethings to do to help him feel more at home.
He could be peeing on the couch because he is afraid to move- or he could have a urinary tract/bladder infection. Check that out. Getting any new pets, you should have a " wellness visit at the vet anyway..