Ambrose is on-loan at NAC this season from City.
And he told SFR Sport: "He has changed everything, from the Under-6s to the first team.
"The youth and the first team are in the same building, and they let us stay in contact with the younger players. It is a bonus if boys of ten or eleven years play in the same way, especially when you try to play soccer from the back."
On Guardiola, he continued: "With him, it's all about ball possession and more ball possession. If you make a stupid mistake, he stops the training for five or ten minutes to talk about the wrong pass. After he has stopped the game for ten minutes, you do not want to lose the ball again."