Back in the day, we had to use firewood to heat up the bath.
But nowadays, everything is done automatically and the machine will let you know that the bath is ready by its speech.
ご質問ありがとうございます。
"Back in the day, we had to use firewood to heat up the bath."=「昔は薪を使ってお風呂をお湯を沸かしていました。」
"But nowadays, everything is done automatically"=「でも今は、全てが自動になっていて」
"and the machine will let you know that the bath is ready by its speech."=「機械が音声でお風呂の準備が出来たことを教えてくれます。」
ご参考になると幸いです。