It's a real mistake to frighten, scold, intimidate your puppy in any way, shape or form. You'll ruin his trust in humans and your relationship with him. Swatting the newspaper at a table top in order to frighten him teaches him NOTHING except that humans are unpredictable and scary. Telling him "NO!" loudly or sternly teaches him NOTHING about potty training or anything else except that humans are unpredictable and scary.
Dogs do not think like humans in that they do not have morals, do not think in terms of "right or wrong." The do not have our value system. They do not think going potty inside is "wrong." Going potty on the floor is the same thing to them as going potty out in the woods. They're dogs, they do what dogs do until we train them. Training is about teaching, showing, patience, consistancy, trust. Your puppy MUST trust you in order to pay attention and try to figure out what you're trying to show him. He does not speak your language. He does not know human ways of acting in a house. You have to show him. Showing him takes time. His control of his little baby bladder and bowels takes maturity before he can even hold it for any length of time. The average time for reliable house breaking is about 6 months of age. My Doberman was almost a year old before he was reliable. I've had dogs who were 3 months old. It varies.
When you scold your puppy even when you do catch him in the act, the way a dog's mind works is that he does not know that you mean that going in the house was the no no. He can perceive it to mean that going at all is a no no and he will then try to hold it. He will tend not to go in front of you when you take him outside. He will hold it inside until he can't anymore and will tend to go behind furniture to hide it. You have to remember that dogs do not rationalize the way we do, do not have a sense of OUR right and wrong, do not think going potty on the ground is a wrong thing to do, do not distinguish between inside and outside for a long time. Once they go inside, it makes it more difficult because they will smell where they went before and think that this IS the spot they're suppose to go because that's what dogs do.
Another problem with scolding a pup for an accident is that he can perceive it to mean, "OK, I am not suppose to go here, but there are many other places I could go which might be OK." There's the back bedroom, the closet, behind the wing back chair. Your puppy, while he's learning is guessing. He does not know what you mean yet. He is guessing and not knowing what he's suppose to do. Since outside is only ONE place, it is much easier for him to stop guessing because that is ONE place where he gets praised and a treat when he goes there....just one place, one possibility. He doesn't have to find out which place anymore when he goes consistantly outside
How he gets from the guessing stage to the knowing stage is done by many, many repititions of being reinforced for behavior. The more he is reinforced with something he loves, like your praise and a treat, the more that behavior will be repeated. That is learing behavior. It is law. If he is reinforced every time he goes inside because going inside is easy, carpet is absorbant, (they like that) it's warm inside....every time he goes inside he is reinforced. It works to go inside. That behavior will tend to be repeated in the future. Now.....every time YOU do YOUR job and supervise him adequately to prevent him from going inside, everytime you get him outside and he goes and is praised lavishly and given a treat, that peeing/pooping outside will be reinforced. It works better for him to go outside. Going outside is much better than going inside because he gets what he LOVES. After many many repititions, he stops guessing because nothing good happens inside, but something very, very good happens when he goes outside. When he is physically able and when he makes that association, he will begin to hold it in order to get a chance to get that praise and treat.....to be taken outside.
Scolding when he's going inside is not necessary at all to train him. It has severely detrimental side effects. If you catch him in the act, just take him out quickly and show him where you want him to go and clean up with Natures Miracle. (Pet stores)
If he has an accident and you really want to use a newspaper, roll it up and hit yourself over the head for not taking him out often enough, for not supervising him well enough.
If you are using a crate, and you need to go out of th room for 1 minute, pop him into the crate. If you cannot watch him for 2 minutes if you're making a phone call or using the bathroom, pop him in his crate. Do not trust that he will not go in the house. You MUST prevent anymore accidents. Take him out often, more often than you think you might need to take him.
Make a log of when he eats, drinks, plays, naps, takes walks, pees, poops. Get so you see a pattern to when he goes in relationship to those things so you have an idea of when it is more likely that he'll have to go.
Normally when you teach a dog something, you praise, treat while he's doing the behavior, not before, not after. However, with potty training, if you praise while he's going, he may get excited and stop mid stream, so you wait until he JUST finishes and you throw him a party, a special treat (hot dog piece, cheese, meat) and loads of happy praise. While he's going, (not before, not after) in a low key, calm voice give him a cue word to begin to attach to this behavior, like, "go pee pee." He can learn eventually after a long time to go on command IF he needs to at all.
With anything you teach your puppy, from sit, down, stay, come, you do not want to make it scary or not fun. Training needs to be fun and rewarding and is VERY fun for both dog and owner when done right....with positive reinforcement and very, very little, if any corrections or aversives. There are wonderful techniques which you can learn. Your puppy can learn better and be happier. Your bond with him can be phenomenal. But if you start off with even mild aversives, intimidation, fear, coercion, you can ruin a dog forever. Remember, this is a baby and the only way for a dog to learn is by reinforcement which is a reward that HE LOVES, not that you think he might love. It has to cause behavior to be repeated in order to be called a reinforcement. Behavior which you don't want, you need to prevent reinforcement for it and it will go away. If puppy is getting into a no no, distract him, give him an alternative and praise and/or treat. Build on behavior you do like by reinforcing it. He will take on those desireable behaviors because they pay off. He will give up the undesireable behaviors if you prevent him from getting a payoff. Your job is to figure out what payoff is he getting from this. You have to watch, think and ask yourself. Sometimes it's attention from a person. Sometimes it's self rewarding like getting into something fun like garbage. Or jumping up on the couter top. If it works for him...if he gets food for doing that behavior, it WILL BE REPEATED. Not because he's bad or immoral but because that is how a dog's mind works. They're hunters, scavengers.....opportunists. They do what works. How else would they have survived for 15,000 years and evolved to be so compatible with humans? They learned how to get along and benefit from being with humans. They're tame and have a bond with humans. BUT, they do not come automatically knowing how to get along in a household....know all the rules and ways. We have to show them. And it takes time.
I recommend you read the book, Culture Clash by Jean Donaldson. It will change everything about how you look at your dog and will show you how to train him in the most effective way, based on the science of learning. I cannot recommend that book enough.
I hope you take an interest in learning how to teach your puppy in a fair, happy and effective way and that you and your pup have a wonderful bond like I do with my four dogs.
Happy training!