If the file is not an mp3, convert it to one:
- After saving your file in Quicktime (or other software), locate the file wherever you saved it.
- You will see that the file looks like "FileName.m4a".
- Click the file to rename it and carefully change the "m4a" to "mp3" and hit Enter/Return.
- It will ask you which file type you want to use, so select "Use .mp3"
Then, open Google Drive in Chrome. If you would like to save the audio file in a particular folder on your Google Drive, navigate to that folder.
Drag and drop the mp3 file from your computer (from the Desktop or by using the Finder) onto your your Google Drive webpage. This will save the file to your drive.
Open your Google Slides presentation. On the menubar at the top of Google Slides, click "Insert" and select "Audio.
You should see your audio file in the list. If not, you can search for it. An audio file only works on a single slide.
The audio will only play for people who have access to the file in Google Drive, so you must share the audio file separately with anybody that will need to hear it.