The changes
The hands
Left hand then right, as the source writes them. A pianist's voicing routinely carries a colour the chord symbol does not spell — a flat ninth over a dominant, a ninth on top of a seventh chord — so the notes printed under each keyboard are what is actually played, rather than what the symbol alone would predict.
Cmaj7
chord 1
LH C2 G2RH E4 B4 D5
A7
chord 2
LH A2 E3RH C#4 G4 Bb4
3rd and b7 prominent
Dm7
chord 3
LH D3 A3RH F4 C5 E5
G7
chord 4
LH G2 D3RH B3 F4 A4