How Do I Play a Sound File in ASL 3?

This is simply not true. As previously stated in your last thread, all you have to do is this:

… And also make sure the asterisk user has permission to read the file AND the directory which it resides, which is outlined here: Permissions - AllStarLink Manual

Have you done this? What exactly is the issue you are facing? What are the error messages you are encountering? We need more info.

You say the “problem” didn’t exist in the other outdated versions but haven’t really presented any problem with ASL3. Proper permissions management is most certainly not a “problem”, it’s actually a really nice fix. It just requires a slight alteration to old outdated operating practices.