Complex sentence: At first, "Islands In The Stream" was not a duet and Rogers was not happy with the recording and only after Dolly Parton was brought in and recorded the song as a duet did the song take off.
Split into simpler sentences: At first, "Islands In The Stream" was not a duet and Rogers was not happy with the recording. Only after Dolly Parton was brought in and recorded the song as a duet did the song take off.