The tool (for .NET 4) can be downloaded at https://www.telerik.com/download/fiddler
See the video below the download link called "Getting started" for a full run thru of how to download/install/run Fiddler
1.Once you have this tool installed please run it.
2.Once Fiddler is running please open a browser and recreate the issue.
3.Once you have reproduced the issue in the web browser please switch back to Fiddler and open the “file” menu and choose “Save -> Session(s) -> in Archive.zip”.
4.Once you have the zip file please send it to us.
Note: see this KB article if you access EP using https:// (encrypted SSL) and make these changes once they have Fiddler installed