If the file url points to a real mp3, you should be able to pgSoundLoader() to play and load controls. However, the player controls do not have forward and back buttons. Instead the idea is to just click in the progress bar to move forward and backward. You could add forward and backward buttons that move the playhead based on its current position using pgSoundControl(). Similar to Netflix, the back button could move back 10s and the forward button would move forward 10s.
If you cannot get that you work, send me the file created by your recorder and I'll take a look.