Scheduled Audio Player for School #3 (Sch3SAP) is a very basic Free and Open Source software, commissioned by my school authorities, that can be used to automatically play chosen audio files. Available in Ukrainian only, and will not be translated. In order to add an audio file to the queue (1) select the time when it starts playing and provide the path to the file (2). You can select a scheduled audio in the queue and remove or edit it (3). Make sure to enable the timer (4) after you've done. The settings window (5) allows you to export or import your audio setup. There is also an option to disable automatic deletion, so you can run all the audio files every day without re-adding them.
The features described above are present in the version 1.2. Sch3SAP 2.0 is a completely different highly simplified program! (see the 3rd image) The times are hardcoded (predefined) to follow school schedule, so you need to select only the class bell and the recess bell audio.