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.
C7
chord 1 · chord 4
LH C2 G2RH E4 Bb4 D5
F7
chord 2
LH F2 C3RH A3 Eb4 G4
Bb7
chord 3
LH Bb2 F3RH D4 Ab4 C5