All pups are different... I have learned that
, Bestia, my oldest was already paper trained when I got him at 8 weeks, once he was home with us it was literally a few weeks before he got the hang of it, smart cookie he is.
However, this new puppy we have now, he has been home with us for just over a month, and we still have problems, you just need to be very patient; for us we have figured out his routine and schedule, so once we see its time he goes out at takes care of business, but if we miss it he will just let go wherever he is (and I really mean it, he has peed his bed a couple times!!), he still doesn't seem to grasp the concept of walking up to the door and let us know he has to go
its frustrating, specially if I compare him to my other dog, but every dog is different and some may just take longer time to learn. He is already 18 weeks, we got him at 11, however, before us, he was never taught to go outside or anything like it, so its all new to him. Not to mention the temperature here doesn't work in our favour right now either
With my older dog every time he went up to the door to go out, after he poop-pee he would get a treat, and that seemed to help, now you don't want to do that for long LOL because our little guy then he just wanted to keep going out the door all the time so we would get treats. That has changed.
You just gotta be patient and consistent.