Hello. Welcome to JustAnswer.com. My name is XXXXX XXXXX X'll be happy to assist you today.
The "auto" mode will need to be set up under the installer setup. I have posted the link to the manual below. Page 6 shows you how to enter the setup menu, then you will press "next" until you get to setup #12, then set that to "1", then press "done". You will then be all set up for auto mode.