24.84A practical exercise on “Happy Birthday”

Use C major for convenience.

First play melody plainly with:

C, F, G7

Then use seventh/extended colors.

Try to keep top melody clear.

For an intro:

Dm7 | G13 |

Then start.

On the repeated phrases, add a little more harmony.

At the final cadence try:

Dm7 → G7 → Cmaj7

then tag the last phrase and finish:

Fmaj7 → Fm6 → C6/9

The point isn't to create the definitive jazz arrangement. It's to combine the tools consciously.