Ты could try giving him/her a reward whenever he/she pees where their supposed to. then your dog will learn that if he pees in that place, he/she gets a treat so it will do it еще often. hope this helps!
Take the pup outside after: sleeping/playing/eating. Also when he has been inside for a while. Give him praise when he does it outside. Takes time but he will learn. Often small Собаки use еще time than bigger dogs.