When you have group presentations that contain files with 'audio', the following steps allow participants to hear the shared audio as well as the presenter's voice...
Step 1: Open your file onto a browser tab.
Step 2: Select 'Share Screen' from the bottom panel of your video screen.
Step 3: Select your Browser Tab selection (Chrome, Firefox, Edge, Safari, etc.), then check the box or toggle on for 'Also Share Tab Audio'. Do not select the 'Window' or 'Entire Screen' option, as it does not allow for sharing 'audio' files.
Step 4: Click 'Share'.
Step 5: As the host, if you hear double audio or feedback, hover your cursor over the 'shared screen' browser tab, right click on your mouse and select 'Mute Site'. This will prevent the host from hearing double audio (audio through the video and audio from the presentation). All other participants should hear the audio correctly.