In the upper left hand corner of your screen, open the Apple menu, then System Preferences
In the System Preferences screen, click "Sound"
In the "Output" tab, select "Meeting Owl Pro" and then close System Preferences.

Students in-person

...

AND online: using Zoom

N.B.: If your students are completely online (no in-person), amplification in the physical classroom you are in is irrelevant to them.

...