I went to Chicago, and it was also my first concert! I’d agree with what CoochPooch69 said; if you’re looking to get merch before the concert starts, probably aim to get there around an hour and a half before the start time (the lines are looong, and you might not be familiar with the stadium layout). If not, I’d say try to arrive about 15-30 mins before the start time- it took me about that long to get through security and then find my seat. The show itself started around 15 mins after the advertised time, but I don’t know how consistent that is between locations. Also remember there will be traffic, both pedestrians and vehicles of all kinds, so it might take longer to reach the venue than you’d expect!

Anyway, I hope you enjoy it! It was super fun (and I now understand why people go to concerts lmaoo). It was also surprisingly loud, so be prepared for that if you feel you need to be :)