How do I add audio clips to Google Slides?

Audio in Google Slides:

You can insert MP3 audio files into Google Slides. These files must live in your Google Drive in order to put them into your slides. You can download MP3 files and put them in your drive, or you can create them. This tutorial is about how to use Screencastify to create MP3 files saved in your Drive automatically and available to add to Google Slides.

Creating the audio files:

Use Screencastify in Google Chrome. If you don't have it installed, go to the Chrome Webstore and search screencastify.
Click on the extension icon to start the recording interface.
Record a screencast. Don't worry, we won't be using the video part that is recorded.

Exporting the audio:

Once you stop the recording, a new tab will open with the video and a panel on the right side with saving/sharing options.
Select the "Export Video" option at the bottom of that window, and then select "More options" from the pop out window.

From the next window, select "Export as MP3"

This will send an MP3 file to your Google Drive in a folder labeled Screencastify.

Inserting the audio into a slide:

You can find the audio file in your Google Drive and rename it.
Then, in your slide, select the "Audio" option from the "Insert" menu.

You can search the title you renamed your file or navigate to it. Sometimes the file does not appear in the navigation, so searching may be the best option.