This tutorial teaches developers how to use the Agora SDK to play audio files during a video call on Android devices. The author provides step-by-step instructions, including adding dependencies in Gradle, adding permissions in the Manifest.xml file, creating an instance of RtcEngine, loading and playing audio files, adjusting volume, and stopping or resuming audio playback. The tutorial also explains how to integrate the play audio feature with the Agora Video Call SDK and provides additional resources for further learning.