Hey Erik,
I’m happy that it works for you too. Yes the folder /var/ipfire/ovpn/google-authenticator and /var/ipfire/ovpn/google-authenticator/otp-config were created manually because i wanted an output directory for the secret files an the otp-config files. The directories can be created during installation. The barcode is a picture so if you redirect the output into a file the barcode is not there. But with the URL you can show the barcode.
Greetings
Steffen