1) I converted the CD attached to my English conversation book into MP3 format and listened to it even outside.
2) I listened to the CD that came with my English conversation book even outside.
1) "英会話の本の付属のCDをMP3形式に変換し外でも聞いていた"
I converted the CD:CDを変換した
attached to my English conversation book :英会話の本に付属している
into MP3 format :MP3形式に
listened to it even outside:外でも聞いていた
2) "英会話の本の付属のCDを外でも聞いていた"