I have two and they both sleep a lot
They love to go outside for walks and they do have times during the day when they will run around and play, but naps seem to be high on their to do list. He may get a little more active as he gets use to you and his new surroundings, but as long as he has been to the vet and you know he's healthy , don't worry, he's probably just a laid back kinda guy.
Cathy, mom to sarge and Lexi