How can I create a video of what’s on the screen?

Swipe down to access the quick settings from any screen, and then click the “Screen recorder” icon to create your recording (In the second page or click “Edit” icon to add tiles).
For additional set up options, go to the main menu -> “Settings” ->“Advanced features”->“Screen Recorder”
Note: Available settings and menus may vary depending on device model and software version.