CL Draw rules

[Potemy]

They'll have to win by at least two goals, you mean.

Just count any away goals as two goals.

[Nampion Chancy]

Not necessarily, it's only in case of a draw on total goals that the team who have score more goal away win. Example:
your team win 3-1 at home and lose 0-1 away that doesn't make a 3-3, you score 3 goals and your opponent score only 2 ( even if one of them was away) that mean that you qualify. But if you win 3-2 at home and loose 1-2 away, in that case it's your opponent that will be qualify, 4-4 in the two legs but 2 goals away for your opponent versus only one for you.