Refer to this page Mobile Core is also configured with the AppID. This is the ID that matches the mobile application with the configuration published in Adobe Platform Launch.HTH.
Make sure we use the 'Publishing Flow' to publish all the resources by adding in the library, in the Launch console. Only then "https://assets.adobedtm.com/file-staging.json" would be available. Hope that helps. Cheers,Wasil