Open QuickTime Player
Click File
Select New Movie Recording
Click the red Record button
Use the arrow next to the Record button to choose the camera and microphone
Click the red Record button again to stop
Click File
Select Save to keep the video
Open Photo Booth
Click the red camera button
Click the stop button when finished
Save the video if prompted
Use the Camera app if available on your Mac
Select video mode
Click the record button
Click the stop button when finished
Use a third-party screen recording app if you want to record your screen
Open the app
Choose screen or camera recording
Click Record
Click Stop when finished