In order to는 무언가의 목적이나 의도를 표현해요. 동의어로는 so as to, as a means to, so that 혹은 그냥 간단히 to가 있겠네요.
예: I put on music at night in order to calm down
= I put on music at night so as to calm down
= I put on music at night so that I calm down. (나는 밤에 편안하게 있기 위해서 음악을 튼다.)
예: In order to understand, you may need to take notes.
= As a means to understand, you may need to take notes
= To understand, you may need to take notes. (이해하려면 필기를 좀 해야 할지도 몰라.)