Add a new colum with a button to field collection
Use the Link Module to add a link field to your field collection


  With this module links can be added easily to any content types and profiles and include advanced validating and different ways of storing internal or external links and URLs. It also supports additional link text title, site wide tokens for titles and title attributes, target attributes, css class attribution, static repeating values, input conversion, and many more.


And add the relevant bootstrap class to the output through the manage display UI.