YOU SAID:

And I had to turn it on exactly at the moment when I put on the headphones.

INTO JAPANESE

そして、ヘッドフォンをつけた瞬間に電源をオンにする必要がありました。

BACK INTO ENGLISH

And the moment I put on the headphones, I had to turn them on.

INTO JAPANESE

そしてヘッドフォンをつけた瞬間に電源を入れなければなりませんでした。

BACK INTO ENGLISH

And the moment I put on the headphones, I had to turn them on.