Before you get a small four-legged friend in the apartment, you should know how to teach it to the street toilet. Even if your pet will behave and ease itself in the tray or other designated place in the apartment, it will be very difficult to get rid of the smell. Besides, as long as your pet is small, it is quite acceptable, but when he grows up? He just physically will constantly overshoot the tray. So it is better from a young age to accustom the dog to "walk" on the street.
If your dog is very small, he would not be allowed to go out at least until the age of one month. That is, as long as all the necessary vaccinations would be done. This time should be spent teaching him about a certain place at home. Yes, you should teach the puppy to the street toilet from with this. To begin with, you should limit the movement of the dog in the apartment to a certain space and put newspapers there. Maybe, it will be a completely small room in an apartment or enclosure. It is necessary to praise the dog and give him different goodies every time he "eases himself" on the paper. Gradually, every few days take away one newspaper from the floor but continue to monitor that the puppy would "ease himself" only on paper but in any case not on the floor. When the puppy does everything right - praise him; when wrongly - punish him but not strictly. Dogs feel good emotions of the owner, therefore, sufficiently it is enough to express your dissatisfaction with voice. Never beat the puppy and yell at him in any case. So, gradually remove the paper leaving only one, still making sure that the dog went to the bathroom only on it. When it will be only one newspaper, you could put it in the tray to keep your house clean. The first phase of training is successfully done.
Further, when all the vaccinations are done and the vet gives the nod to the street walks begin to accustom the puppy to the toilet on the street. Walk with a small puppy 5-6 times a day. Schedule his walks so that the dog would have to walk immediately after sleep or food, just so he goes to the toilet. Going for a walk, take a paper from the tray, put the puppy on it, and show him what to do. Gradually, the dog will get used to and the newspaper is no longer required. Naturally, if he eases himself on the street, it is necessary to praise the pet and give him some yummy, but for the mess at home (this will be happening at first, this is normal) punish him a little. You can also teach the dog that he asked to go on the street when he wants to ease himself, for example, came to the door and scrape it with his paw. To do this, it is necessary to take the dog's paw and scratch the door when you go for a walk. But, if you walk the dog on a schedule, all the time at a certain time, his organism will get used to it and additional walks are not needed. When the dog will be 1,5 years old you can reduce the number of walks to three times a day.