YOU SAID:
I did not understand the use of this website
INTO JAPANESE
私はこのウェブサイトの使い方を理解していませんでした
BACK INTO ENGLISH
I did not understand how to use this website
INTO JAPANESE
このウェブサイトの使い方がわかりませんでした
BACK INTO ENGLISH
I did not understand how to use this website
You've done this before, haven't you.