Getting the command line olaf application to work on Windows requires a few steps.
Both Ruby and ffmpeg need to be installed on your system and both need to be available on your path.
For ffmpeg you need to copy ffmpeg.exe to e.g. c:\windows\system32 or another location on your $PATH. You can find recent ffmpeg builds for Windows here or here. Download, unzip and copy the exe. Only ffmpeg.exe is needed.
The easy way to install Ruby on Windows is to use the Ruby Installer. Simply install a Ruby environment. Olaf does not need a specific Ruby version: anything Ruby environment above 2.5 will work.
Now you should be able to call ruby -v and ffmpeg -v on the CMD command line.
Download olaf_c.exe here and copy it to a fixed location. For example 'C:/Program Files/olaf_c.exe'
Download olaf.rb, open it in a text editor and modify the “EXECUTABLE_LOCATION” to e.g. 'C:/Program Files/olaf_c.exe'.
Now you can call Olaf as follows, in the directory where olaf.rb is also found:
ruby olaf.rb store test.mp3
ruby olaf.rb query test.mp3