Registering for Alamo Kiosk

I am about to register for the Alamo save time for our upcoming trip. I have previously not had great success with this service so want to make sure I have done it correctly this time.

When asking for the confirmation number do I use the booking number or the supplier confirmation number on my voucher. Bit of a daft question I know but just want to get it right.

Thanks

You should use the supplier confirmation number, as this is the number issued by Alamo.

Thank you :-)