This lesson comes from my Method Book Volume 2.
Below is the lesson for D Major (Page 22) including the scales and chord progressions. The lesson for the Le Petite Rien by Couperin (Page 23) starts 5:16 mins. The lesson for La Volte on (Page 24) starts at 7:13 mins. Be sure to watch the whole video straight through to get an overview and to not miss any info.
Below is a recording of the duet with my friend Natasha Pashchenko. If you are playing the duet without a teacher just play the top line on its own.