Fugitives - The Farmstead
Upon reaching the farm, choose either option to get rid of the old people. Now, go to the main room and you'll Leo to interact with the banjo and Vincent to interact with the piano. Select the easy difficulty and have both characters play about 15 notes in a row successfully to trigger a cutscene. Achievement unlocks.
This achievement can be seen in the video guide at 5:06:NOTE:
Achievements are only available to owners of the game. Players using the "Free Trial" friend pass will NOT unlock achievements.