Windows is the only operating system supported.
All methods of running BZ are equivalent; the only difference is in the way that BZ is opened. Also, all methods require a file of the type <file>.brz. These files are generated by MOPAC automatically when keyword MERS is present. Use whichever method you prefer. Start by putting the program BZ.exe in a folder on your machine, in a location of your choice. A suitable location would be one where it is not likely to be accidentally deleted.
This is probably the easiest method. To set this up, right-click on a .brz file, then chose "Open". Select "Select a program from a list of installed programs" then click on "OK". Browse to the BZ.exe folder and left-click on BZ.exe. Click on "Open". That will take you back to the "Open with" window. Check "Always use the selected program to open this type of file" then click on "OK"
Once the default program is set up, double-clicking on a <file>.brz file will start BZ running.
Copy the BZ.exe file and paste a shortcut onto the desktop so that it is an icon. Then select a .brz file and drag and drop it onto the icon. If a .dat file is to be used, select the .brz file and the .dat file and drag and drop them onto the BZ icon.
This option is only useful when "drag and drop" cannot be used.
The command:
"C:/<folder that holds BZ.exe>/BZ.exe" <file>.brz [<file.dat>]
will run BZ with an optional <file>.dat. If used, the <file>.dat file should contain information on the path through k-space that is to be drawn.
All the data that are typed into the a BZ run are saved and written to a file <file>.dat. This file can then be used to re-generate the band structure or little groups for the system. At the start, when exploring the k-space of a solid, mistakes will be made. This is expected. Eventually a set of data will be typed into BZ that will produce a good graphic or output. At that point, rename the <file>.dat to give it a new name that indicates what it represents. For example, a surface that includes the k-space point "L" in the phonon spectrum of diamond, done using a file "Diamond for Phonon with ops.brz", would be named "Diamond for Phonon with ops.dat". Such a file should be re-named, e.g., "Diamond for Phonon with ops surface L.dat".
Eventually a set of data-files will be made, with each data-file representing one detail of the band-structure in the Brillouin zone.