Complex sentence: The band worked on the track to give it a "spacier sound" but were displeased with the result so took the song to producer Nellee Hooper, who stripped "Running" down to the basics.
Split into simpler sentences: The band worked on the track to give it a "spacier sound" but were displeased with the result. They took the song to producer Nellee Hooper, who stripped "Running" down to the basics.