Easy achievement to get. Instruments are in most levels but first and easiest place is Centre Perks 2.0.
Just go this South-East room and press
on any of the instruments and sit there for 1 hour game time.
To not get in trouble do it during free period. Once you come off the instrument after an in-game hour the achievement will unlock. (1 hour in game time is about 1 minute IRL)