Years ago, my dad showed me the basic elementary rudamentary concepts
behind chording to fiddle tunes while playing piano. And here
years later, I'm going to try to explain what he said. So, what
my Dad said to do was to play a left hand single bass note on
beats one and three, and a right hand triad chord on beats two and
four. You make sure that all the notes are members of the
chords you need to use, in this case G, C and D chords.