려면

in order to, if you want to

Sets up a goal, and the rest of the sentence says what it takes to reach it: 살을 빼려면 어떻게 해야 해요? "what do I do to lose weight?", 잠 깨려면 커피 한 잔이 필요해 "I need a coffee to wake up", 만들려면 몇 명 있어야 해요? "how many people does it take to make this?". The goal has to be something the subject intends, so it does not work for accidents. After a consonant it appears as 으려면. It is the conditional of 려고 (intending to).