To expand on how to use private file uploads in general … what you want to happen is this sequence:
A record or “thing” is created to save the private upload onto.
The record is passed into the options, usually with a dynamic search.
The upload to S3 is triggered, in this case using the “save” action.
When the upload has finished, the “is saved” event triggers.
At this point, a URL to the upload in S3 is available.
The URL can now be stored in the database, it can be stored on a “file” or “image” type.