Robert,
You don’t need to add the scene id to the ST_Scene_API shortcut. The only change needed in the ST_Scene_API shortcut is to change the pat valve in the dictionary to your pat.
To create a scene shortcut, duplicate the ‘test scene’ shortcut, rename it as necessary and change the sceneid value in the dictionary to your scene id. Your duplicated scene shortcut will call the ST_Scene_API to send the Post request to the SmartThings Scene API. To make additional scene shortcuts, do the same thing by duplicating the ‘test scene’ again
To execute your scene with Siri, just say “Hey Siri, execute yourscenename shortcut”
Let me know if this works and if you have any further questions