In order to edit any files you must be inside WebDav as you cannot do this directly from inside your CRM account within the File repository.  

You can however, add folder names inside Files and upload files into the File repository which will then be shown inside your WebDav file network. 

We have set up this plug in which is easy to set up and provides you with some really powerful features.  

To set up WebDav on your PC click here.