There is now a graphical user interface. You must have Java installed to run this interface, which you can get from
http://java.com/download.
See the original post for the binaries and instructions.
For Windows, the zip file contains all the binaries you need: pdfreflow.exe, pdftohtml.exe, and the Java jar file.
For other platforms, you must already have pdfreflow and pdftohtml installed, and they must be in your path.
There is a Help button that will bring up some online help.