There are two ways to add audio to a slideshow: by recording audio, and by uploading audio.
Recording audio
It is possible to record audio to add to your slideshow. To do so, click on the "Audio" tab.
You will see four buttons.
Here you can record your own audio clips. If the recording exceeds a minute, it will be split into different files.
When you're done, you can give your audio file a name. Don't forget to save it with the "Save" button, or delete it with the "Delete" button when you are not happy with it. You can also download the file to your computer using the "Download" button.
Uploading audio
It is possible to upload audio files (mp3, ogg, wav). The maximum file size for uploads is 32 MB. Audio can be uploaded in the same way as images. Make sure to copy the reference link!
Attaching audio to your slideshow
You can attach these files to the slides in the "Slides" tab by clicking on "Insert" and then "Audio".