because this is a python script, you'll need to have python 3 installed. You can use systemd-multiunit-genconf.py to generate the default config file from your system's man systemd.unit output, or you can use the pre-generated generator.conf. Once you have your config, place it at /etc/systemd-multiunit-generator/generator.conf and place systemd-multiunit-generator.py under /etc/systemd/system-generators/ and make sure it's executable. You can place your multiunits under /etc/systemd-multiunit-generator/system/ with the .unit file extention, and it will also load drop-ins from *.unit.d/*.

Example unit(s) can be found here in the test_source directory.