There is so many ways to deal with this,and we all have different ways we are all different when it comes to training our dogs.now when they do mess in the house i used to take them directly outside, i had a real hard time with my Newf she spent her first 6 months of her life in a kennel and what do they do? go every where so all i did was when she would mess in the house id say "Shame on you" or "that's bad" and take her directly outside and she new i ment buisness after a week or so, i was scared because she was 6 months old and i thought she was ruined but she is great now been accident free for months.
Not all of us are lucky that way,my first dog Maggy we paper trained her WHICH WAS THE WORST THING TO DO,and she was a year old before she learned that the outside was her place to go..Just keep up with them and in no time im sure Sam will get the hint!!!