used to emphasize that something is naturally so or should be expected; 'as is only natural' or 'not surprisingly'.
当然のことながら、試験前は準備が必要だ。
Naturally, you need to prepare before an exam.
当然のことながら、部屋を使ったら片付けてください。
As a matter of course, please tidy up after using the room.
当然のことながら、安全確認を忘れてはいけない。
It goes without saying that you must not skip safety checks.