Here’s what worked for me:
[Note: The following solution worked for PDFs - not sure what type of file/document you’re using, you may need a different method for other document types.]
Since I had lots of docs to preview, I used a repeating group (RG).
Then, in the RG cell, draw an HTML element. Within the element, I used <iframe src= [ ENTER YOUR "CURRENT CELL’S [PDF FILE ] HERE ]
/frameborder=“0” width=“580” height=“569” allowfullscreen=“true” mozallowfullscreen=“true” webkitallowfullscreen=“true”>
That should do it. If you want to add visibility options (such as to buttons and so on you can do that too. I used a preview option (the small view) and then used a button to send it to a larger popup that let’s you see the file in all its glory.
A note about the [ENTER CURRENT CELL’S PDF FILE HERE ]: for this you can just use the data field name you used to store the PDFs in; you do not have to use any of the subsequent syntax options such as ’ ‘s URL’, ‘:saved to S3’ or ’ ‘s file name’ - just stop at the Current cell’s [PDF field name].
Hope this helps,