Complex sentence: Around the same time, Francis took a job as a singer for demonstration records, were brought to the attention of established singers and/or their management who would subsequently choose or decline to record the song for a professional commercial record.
Split into simpler sentences: Around the same time, Francis took a job as a singer for Demonstration Records. These records were brought to the attention of established singers and/or their management who would subsequently choose or decline to record the song for a professional commercial record.