The midfielder has struggled since his summer arrival, but Koulibaly says he has the support of his teammates.
He said: "I think that for a guy like him, getting to a great club like Napoli is the best thing: he has to learn because Italian football is completely different from the others, he's still immature, but I think on the right path, we have seen in his appearances that he is a quality player.
"Advice, of course I talk to him a lot, (Faouzi) Ghoulam does it, he's like a big brother to him. We know that Adam has a huge talent, I help him as much as I can, in training we try a lot of physical contact so to get used to it. We know that Italian football is challenging and a great tactical effort is required for a striker."