Open your Google Slides presentation and go to the slide where you want to add music.

Click on "Insert" in the top menu bar and select "Audio" from the dropdown.

Choose an audio file from your Google Drive and click "Select" to insert it.

A speaker icon will appear; click it to access playback settings.

Adjust options like autoplay, looping, and volume in the "Format options" panel.

Move the speaker icon to your preferred position on the slide.

Preview the slide to ensure the music plays correctly, then save your changes.