V + 었더라면 works with past tense verbs to say 'if I'd done V...'.
Because it is used to express regret, it is often accompanied by (했)을 것이다 to form 'if I'd done that... I would have...':
우리가 일찍 왔더라면 더 좋은 자리를 찾을 수 있었을 거에요.
If we'd come earlier we could have found better seats.
제가 과식을 하지 않았더라면 안 토했을 거에요.
If I hadn't overeaten I wouldn't have vomited.
제가 선생님의 조언을 받았더라면 시험을 잘 봤을 거에요.
If I had listened to my teacher's advice I would have passed the exam.
제가 2분 빨리 집을 나갔더라면 버스를 안 놓쳤을 거에요.
If I'd left the house two minutes earlier I wouldn't have missed the bus.
먼저 그들이 저에게 물어봤더라면 제가 그들에게 여기에 오는 것은 시간 낭비라고 말해줬을 거에요.
If they'd asked me beforehand, I would've told them that coming here was a waste of time.
제가 지난밤을 새우지 않았더라면 오늘 수업 중에 잠에 들지 않았을 거에요.
If I hadn't stayed up all night I wouldn't have fallen asleep during class.
제가 한국에서 이사하지 않았더라면 아내를 못 만났을 거에요.
If I hadn't moved to Korea I wouldn't have met my wife.
제가 찜질방 말고 호텔에 머물렀더라면 지금 등이 안 아플 거에요.
If I'd stayed in a hotel instead of a jjimjilbang I wouldn't have a sore back now.