Harlowe 3.x was deliberately changed so that it automatically re-show the current Passage whenever the page is refreshed. It includes no configuration settings or macros which allow you to override this behaviour.
Because of this you wouldn’t be defining your audio tracks within whichever passage you have marked as the ‘start here’ one. As Howler requires you to use JavaScript to define your tracks I would suggest using your project’s Story Javascript area to do this activity.
Another possible option would be to replace your existing Howler based audio implement with ChapelR’s Harlowe Audio Library which has been deliberately designed to work with Harlowe, so it may better handle the situation you describe.