Here is how you turn it on.
Once you choose an album or playlist and it starts playing, tap thethree dotsicon in the upper-right corner.
TapSleep Timer, then choose a duration.

you’re able to even set it to wait until the end of track.
You will see a confirmation, then returned to the track you’re currently listening to.
Using the Sleep timer will limit noise to a certain amount of time.

Tap thethree dotsicon in the upper-right corner when a song is playing.
The sleep timer will show a green moon and display how much time is left.
Scroll down and tapTurn off timerto keep the music going.