I know exactly what you feel man as I once had this problem too. Away goals matter a lot as they can be the deciding factor in games, so if Chelsea draws 0-0 at Home and win 1-1 away they'll go through because of that away goal. If they win 1-0 at Home and lose 2-0 away they'll get kicked out as they've lost 2-1. BUT if they draw 1-1 at Home and lead 1-0 away, the other team will have to score 2 at Home in order to advance because they conceded too many away goals. Extra time and penalties only happen if the score is the same on both legs. It's really confusing man I understand, but if you're watching a game where this applies just look back at this list and it will give you an idea on how it works, this is the easiest way anyone will explain it and I hope it helps.

The series would be tied. There would be extra time at the end of the 2nd game followed by kicks from the penalty spot if needed.

Extra time, but if it was 2-1 it would be decided on away goals rule

So I just wondered if Team A 1-0 Team B. After the first leg.... The Team B 1-0 Team A. Soo... If We followed as UEFA Champions League rules. Which team will advanced? Or is it will be an extra time?

Note. This case is during the R-16.