To power on your iPod, press and hold the Sleep/Wake button until you see the Apple logo, then release it. If your iPod is unresponsive, you may need to perform a force restart. All you need to do is hold down both the Top and Volume Down(or Home button if you have it) buttons at the same time for about 10 seconds. During that time, you’ll see the iPod turn off, then the screen will display the Apple logo, at which time you can release those buttons. [1] X Research source
Instead of powering your iPod off, you can also wait for it to go into sleep mode. If you don’t touch it or play music for a while, the screen will dim and eventually turn off. When the screen is black, your iPod is sleeping. While sleeping, your iPod conserves battery, as if it were off. However, it is faster to play music again since you don’t have to restart it.
Slide the switch to the “Off”(white) position to turn your iPod back on. If your iPod is unresponsive, you may need to perform a force restart. To do this, press and hold the Sleep/Wake button and the Home (or Volume Down) button until the screen turns off. The Apple logo will appear and you can release the buttons. [2] X Research source