1. On your Mac, open QuickTime Player. If you don't see it in the Dock, you may search for it using the magnifying glass in the top-right corner.

2. In the QuickTime Player app on your Mac, choose File>New Screen Recording to open Screenshot and display the tools. To see only a portion of the screen, drag the frame to reposition it or drag its edges to adjust the size of the area you want to capture or record.
Action buttons: Close, Capture Entire Screen, Capture Selected Window, Capture Selected Portion, Record Entire Screen, Record Selected Portion. 

3. Click and select Options if you want to make additional customizations. The available options vary based on whether you're taking a screenshot or a screen recording.
Save to: options include Desktop, Documents, etc., as well as Other Location where you can specify where you want the file to save

Timer: options include None, 5 seconds, and 10 seconds

Microphone: options include None, ZoomAudioDevice, MacBook Pro Microphone

Options: options include Show Floating Thumbnail, Remember Last Selection, and Show Mouse Clicks.

4. Capture the screenshot or start the screen recording.

For the entire screen or a portion of it: click Capture.

For a window: move the cursor to the window, then click the window.

For recordings: click Record. To stop the recording, click the Stop Recording button on the menu bar.

5. When the Show Floating Thumbnail option is set, you can do any of the following while the thumbnail is briefly displayed in the bottom-right corner of the screen:

a. Swipe right to immediately save the file and make it disappear.

b. Drag the thumbnail into a document, an email, a note, or a Finder window.

c. Click the thumbnail to open a window where you can mark up the screenshot/trim the recording or share it.

6. You can upload this screencast to Canvas Studio or YouTube to share in your Canvas course.