Power on: press and hold the Power On Button until the phone is switched on.
Switch off: simultaneously press the Side Key + one of the two volume keys (your choice).
Forced restart: press the Volume Up Button (release it immediately), press the Volume Down Button (release it right away), press and hold the Side Power Button until the phone is turned off. It will turn itself back on.
Unlock the screen: raise the iPhone from a surface to make it light or a touch anywhere on the screen.
Then with the screen on, a slide from the bottom to the top.
Screenshot: Power key + Volume Up
Control Center: a slide from top to bottom starting from the top right (Network / WiFi / Battery icons) of the screen.
Notification Center: a slide from top to bottom starting from the top left (from the digital clock) of the screen.
Exit an application: drag the bottom of the screen upwards.
Multitasking: drag the bottom of the screen upwards without releasing.
Close the open apps in Multitasking: long touch a preview to make a red icon appear.
Configure Face ID: Go to the settings and select "Face ID and code".