How do I turn on / restart Phone (2a)?

There are two ways to do so:
1. Combination keys
Press and hold the Volume up and Power button at the same time to bring up the operation interface, which offers four options: Emergency, Lockdown, Power off and Restart. Click on Power off or Restart to turn off or reboot your phone.
2. Control center panel
Slide down the status bar and pull down the control center panel, click the icon in the bottom-right corner to bring up the operation interface, with the same four options: Emergency, Lockdown, Power off, Restart. Click Power off or Restart to turn off or reboot your phone.

Note: if the phone is frozen and the screen is unresponsive, you can force a shutdown by holding the power button for 15 seconds, or force a restart by long-pressing the power button for 15 seconds or more.