YOU SAID:
how am I supposed to know how to do this
INTO JAPANESE
どのように私はこれを行う方法を知っているはずです
BACK INTO ENGLISH
How should I know how to do this
INTO JAPANESE
どのように私はこれを行う方法を知っている必要があります
BACK INTO ENGLISH
How should I know how to do this
You've done this before, haven't you.