Article in English: Click the magnifying glass-shaped icon in the top-right corner of the screen. This will search your Mac for the QuickTime app. It should be the top search result in the Spotlight search. Doing so will open QuickTime. This menu item is in the top-left corner of your Mac's screen. A drop-down menu will appear. It's near the top of the File drop-down menu. Clicking this prompts a "Screen Recording" bar to open. It's the red and silver circular button at the bottom of the Screen Recording bar. Doing so brings up a screen selection box. You can also click ∨ to the right of the recording button to prompt a drop-down menu with microphone options and the option to enable or disable alerts for mouse clicking in the recording. This will prompt QuickTime to begin recording your entire screen's contents.  Alternatively, you can click and drag the selection box to surround a section of your screen and then click the "Record" button again to record only the surrounded section. To stop recording, click File in your Mac's menu bar, then click Stop Recording in the drop-down menu.

Summary in Vietnamese:
Mở Spotlight. Nhập quicktime vào Spotlight. Nhấp vào QuickTime. Nhấp vào File (Tập tin). Nhấp vào New Screen Recording (Bản quay video màn hình mới). Nhấp vào nút "Record" hình tròn có màu đỏ và bạc nằm cuối thanh Screen Recording. Nhấp vào bất cứ đâu trên màn hình.