How to show File Preview or Downloadable link in TimeLine Tab using Freedom UI

Hello,

I am currently working on Integrating my Custom Object Data on Time Line tab in Contact form page, I have followed this link to accomplish this .

Now I want to show the file attachment preview or a downloadable link in the timeline tab.

This is what I have tried:

1. In my first try, I tried to save the files in separate object and add that object as lookup field in my custom object.
   1. Result: It shows the name of file only in timeline object
2. In my second try, I directly introduced  a file datatype field in my custom object,
   1. Result : It shows the raw file content in preview.

Also, How can we change the visibility of this field as I only want to show it if it has any value. I am using an online instance.

Can any one guide me on how to do this?

Thanks in advance for your support!!