Complex sentence: The First Edition (later known as Kenny Rogers and the First Edition) was a country music/rock band stalwart members being Kenny Rogers (vocals & bass guitar), Mickey Jones (drums & percussion) and Terry Williams (guitar & vocals).
Split into simpler sentences: The First Edition (later known as Kenny Rogers and the First Edition) was a country music/rock band. Its stalwart members being Kenny Rogers (vocals & bass guitar), Mickey Jones (drums & percussion) and Terry Williams (guitar & vocals).