polo -config [path_to_your_conf] [your_folder_with_mds] [your_output_path]
If the config is called config.json and it's on your current directory, you
don't even need to specify it.
One more thing
You can run polo with the -daemon option which will start a server serving
your generated content and in case that you change any of the files in the
input folder it's going to autoregenerate the site.