with older iPhones
long press on the top button
to get shutdown prompt
How to restart your iPhone SE (1st generation), 5, or earlier
- Press and hold the top button until the power off slider appears. 
- Drag the slider, then wait 30 seconds for your device to turn off. 
- To turn your device back on, press and hold the top button until you see the Apple logo. 

 
             
                 
                 
                 
                