You can use AirPlay to send only audio to your classroom display, effectively treating it as a big speaker. This might be particularly useful if you'd like your in-class students to hear your remote students through Zoom, but without needing to show their Zoom videos.
Here is a 6 minute video demonstrating how to use AirPlay this way, and discussing various scenarios which might be useful for a hybrid classroom.
AirPlay for Audio
This feature is managed through the volume control in your menu bar. Look in the top-right part of your screen for this icon:
If you don't see this icon, click the Apple menu in the top-right corner of your screen and choose System Preferences. Click the Sound item, then check the box at the bottom of the window labelled Show volume in menu bar.
Now, click the volume icon in your menu bar; you will see a list of classroom displays, just like you would see in the AirPlay menu.
Choose your classroom display, then enter the 4-digit code which appears on your classroom display. Now your laptop will play sound through your display, without needing to share your screen.
To stop sending your audio over AirPlay, click the volume icon again and choose the very top item in the list, usually called Built-in Speakers or Headphones.
Choosing this speaker in Zoom
Zoom may choose to play sound through this AirPlay speaker automatically; if it doesn't, click the up-arrow next to the Mute/Unmute button in Zoom and choose your classroom display in the Select a Speaker section.
Please watch the demonstration video above for more ways you might use this AirPlay audio feature with Zoom.