I'm a Designer by trade (25+ years), but picked up scheduling along the way to fill in the slow periods
Started scheduling using the DOS based version called Finest Hour. Somewhere in the early 90's I attended a 3-4 day long P3 training class at Primavera's then office in Bala Cynwyd, PA.
Over the years I have dabbled on and off with P6, but the last several years (2010-current) my job title has shifted more to scheduling and less design.