Retrieving a a pdf file from a customer specific folder

Hello Sir / Madam

I am trying to store PDF in a customer specific folder and after that wan to retrieve that PDF file from the same app. in doing so PDF file is not loading instead an error loading file web page is opening. Can any one help with suggestion.

https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/FILE-OPENING-MANAGEMENT/td-p/658432