How can I play away first and then at home in the Champions League knockout?

In the first round of elimination, the first place in each group has the right to make a guest appearance before hosting.

In the second round of lottery, two and a half districts were drawn. According to the half-court area, the home and away games were drawn to the semi-finals.

It doesn't mean that 1 is equal to the home team's 3 goals, but when the total score of the two rounds is the same, the team with more away goals will advance. If the total score is the same, then both sides have the same number of goals at home and away. Will play overtime, overtime will not have the advantage rule of away goals. If we draw again, we will enter a penalty shootout.