How to make my Ipod sleep

• To turn the screen off while the music is playing - and for the iPod to keep playing until you stop it, then as Skydiver suggests, use the Settings/Display & Brightness>Auto-lock
• If you mean that you want to play music for a set time and then have the iPod stop playing and go to sleep (a sleep timer),
  • go into the Clock app on the iPod
  • select Timer (bottom menu, at the right-hand end)
  • set the time you want to elapse before sleeping
  • tap the line that says When Timer Ends
  • at the end of the sound options list is a separate entry that states Stop Playing
  • Tap the Stop Playing line (so that the tick appears next to the text)
  • tap the orange Set text at the top of the page
  • the screen retunrs to the timer screen and you will see that the line below the timer now reads When Time Ends - Stop Playing >
  • tap the green Start button to start the timer
  • when the time you set is reached, the iPod stops the music and goes to sleep

When you put the iPod to sleep it will continue to use a little bit of power, dependent on which apps are running while it is asleep. For example, if you are playing music with the display off, power is still being used, to play the music, but it is far less power than when the display is on.

If you turn the iPod off, it will use no power, but be aware that the battery will self-discharge. In other words, if you turn the iPod off and put it away for a few months, the remaining power in the battery will be less than when you put it away. See the following article for Apple's advice on getting the bets out of your battery: Batteries - Maximizing Performance - Apple

To turn your iPod off, press-and-hold the power sawitch until the power off slider appears. Use th slider to turn the iPod off.

To turn the iPod on (from power-off mode), press-and-hold the power switch until the iPod display lights up with the Apple logo. It takes a minute or two before the iPod is ready to use.

Have you tried setting, display and brightness and auto lock? That should tell the screen to turn off. I think the music keeps playing. honestly I don’t use mine as a music player so I really don’t have any experience, but it could be something to try