well I think you are getting it a bit wrong. here's what is called no error housetraining, fast, easy and kind to the dog.
Housetraining is fast and easy if you do the no error method. Basically you take pup outside on waking, before and after eating if he wakes at night (keep him with you in box or crate) during exciting play and by default at about half hourly intervals while he is awake. If he has an accident indoors you wont get excited or angry it is because it is your fault not his. watch pup and you will earn what he does immediately before he goes (sniff the floor, walk in a circle, crouch and shuffle, go to a corner and so on) if you see that behaviour, cheerfully take him outside, carry at first then call him to go with you. If you carry, folding the tail in over his bum can help to "cork" him so you don't get peed on.
when you take pup outside, stay with him till he goes then praise lavishly and give a yummy treat. While he is out there, don't interact with him until he has gone, just stand calmly and wait. Once he is starting to get the hang of it, you cn add in a trigger word so that he will at least pee on request, its useful when taking him in the car or going out and leaving him when he is much older.
He will quickly get the hang of this and start to go to the door when he needs to wee/poo. Praise and encourage this but save the jackpot praise and treats for after he has been. Still take out very regularly as he won't be able to wait for long and still stay with him till he goes.
I do no error because i hate cleaning up mess. if you do get messes in the house, clean up thoroughly with a specialist product( I use zybax from advance burt you can get others) to get rid of the smell as the smell will make him think its where he should go. personally I think pads are a waste of money and confusing to pup as you are telling him its okay to go indoors then you have to tell him it isn't.
Please don't leave your four month old puppy alone. He will get anxious and turn into an anxious dog who can't be left alone without messing in the house or wrecking things.