Congrats on owning an AB! Beautiful dogs they are!!!
Ditto to what Faolmor said. Your puppy will soon realise you want him to toilet on the grass. Just put him out on the grass when you want him to go, and after he goes.... He will soon get the idea.. Our AB was like this in the beginning also, and my bathroom was a disgrace, but they soon get the idea... Dozer hasnt been to the toilet anywhere but the grass in years.. and she is an inside dog!
Goodluck!