App script integration with PDF.co

[Harriswe]

Using an app-script to merge PDF files although the script originally used a Google sheet to pass parameters. However using a Bot to pass parameters to the app-script there is a problem receiving the resulting merged file URL back.

Q: How to you specify a URL path for 3rd party apps like PDF co to store a file, which is relative to where where AppSheet app stores files?

Q: Has anyone had any success using something like PDF.co with AppSheet?

Thank you for any assistance.