Any parameter requiring a file name uses the file:///c:\path\to\file formatused in URLs. For the branch, you can specify any of "current", "previous", or "evaluation" (not case-sensitive).
Note that this particular command does not accept multi-part content from HTTP POST requests so if you are accessing this through a web browser this will not work. You will need to use a scripting language (e.g. Python) to use this in that capacity. The ability for this command to be augmented to accept multi-part content is something that's in our backlog for future enhancements.