First trip to San Siro for ucl game

Hello everyone, I know this was probably asked but I couldn't find it anywhere...
I have a couple of questions:

1. I plan to go with a couple friends to the AC Milan vs Crvena Zvezda game, how full do you think the san siro is gonna be? Are we gonna get the San Siro ucl experience?
2. On the match day, where should we go to interact with the ultras and have the full experience? Will they upload it somewhere or is there a usual place?

Thanks a lot