you will need extract dff2dsf.exe from the zip file
open dff2dsf-122.zip from Windows Explorer (or any uncompress software), then COPY win32\dff2dsf.exe to C:\BIN - or any folder you want.
if your dff files (Track01.dff) under C:\DFF
open "Command Prompt"
in C:
type "cd C:\DFF", it will goto C:\DFF>
type "C:\BIN\DFF2DSF.EXE Track01.dff Track01.dsf", replace C:\BIN to where you saved dff2dsf.exe
repeat above if you have more files.