The striker made his debut off the bench in Sunday’s defeat to Manchester City after completing a £30.5million switch from Sassuolo.
“I spoke to Mancini, he told me that it would be the best choice to test myself in a championship as competitive as the Premier League,” he told Sky Sport Italia.
“I am convinced that I have made the right choice. I think about working hard, helping the team and reaching the highest level as a player.
“I don't have a target, I want to win the most games and maybe even a trophy, the goals will come.”
Scamacca paid tribute to the fans for generating a “fantastic” atmosphere at London Stadium to kick off his Hammers career.
“Incredible emotion,” he added. “The stadium is impressive and the fans were fantastic.
“Too bad for the defeat, but it is the first game and now we only think about working. Everything is different here: from our habits to the intensity on the pitch.”