It will be my first match at San Siro, I hope I'll bring some luck.
I saw like 5 Hellas matches this season and it will be tough to win. They are defending really well, they conceded just 9 goals this season, least in the league together with Juventus. I think their best defender is Rrahmani who defenses in Skriniar way, very aggressive and nice tackling. In the midfield they have 2 interesting names - Veloso and Amrabat. I never rated Veloso, but he is doing well, his set pieces are just great, we have to be careful to not allow him for shot opportunities, because he has great left foot. Amrabat on the other side is more Barella type player which runs as crazy and is everywhere.
However, they have problem with scoring goals from open play, they have 2 strikers Di Carmino and Stępiński and they are more Serie B players, they have 0 goals so far this season. I consider Eddy Salcedo as winger at the moment, but in the last match against Brescia he played as a forward. I think Lazović is their most dangerous offensive player. He is really chaotic player who loses the ball a lot of times, but sometimes he can win duel and create a nice chance for his teammates.
So in a nutshell: score quickly first goal and avoid set pieces for the opponents, especially corners.