Google drive integration

Hi, 

When a user completes and uploads files to the form and then submits them. I want to upload those files to my google drive (I successfully connect to Google Dive Web API)

I am configuring the Integration but I have no idea how to configure the DOCUMENT section, I suppose that an expression should go to indicate which files should be uploaded to google drive (HELP ME WITH SOME EXAMPLES)

This is the users form (how i call the integration?)

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