I have a little boy now he is 11 months old. When he was little like 3 months old I would take him every one and a half hour outside after he would do his deed I would reward him everytime we get back in the house. He got the idea right away. Maxi would associate go outside to pee with getting a treat. I have read that puppies up to 6 months cant really hold it for a long time because the bladder learns to hold around 6 months. When Maxi peed in the house when he was a little baby I would be firm and say What did you do and bad boy

he knew he did something bad and after that you should take him outside make him go and then reward ur pup for being good to go outside. Should help good luck!