Press Shift + Command + 5
Choose Record Entire Screen or Record Selected Portion
Click Options to select microphone, save location, and timer settings
Click Record
To stop, click the Stop button in the menu bar or press Command + Control + Esc
Find the recording in the selected save location
To use QuickTime Player, open QuickTime Player
Click File
Click New Screen Recording
Click the arrow next to the record button to choose microphone and options
Click the record button
Select the screen area or click anywhere to record the entire screen
Click the Stop button in the menu bar to finish
Save the recording when prompted