When I click Alexa Guard in Setting, it just shows "Learn More" button and not button to enable it.
Hello parora, Welcome to Amazon Digital and Device Forum!
I'm sorry about the trouble you have setting up Alexa Guard.
To get started, from the home screen of the Alexa app, go to the main menu, select Settings, then Guard.
Before setting up Alexa Guard, please ensure that you have the latest version of the Alexa app and that your Echo software is up to date.
To update Guard preferences, from the home screen of the Alexa app:
Go to the main menu, select Settings, then Guard.
Select the gear icon at the top right of the screen. Preferences include: selecting Echo devices, receiving Smart Alerts, adding or removing smart lights for Away Lighting, and linking or delinking your home security system.
Once you set up Alexa Guard, just say, "I'm leaving," to switch to Away mode. The light ring on your Echo devices will animate with a rotating white light to indicate when Guard is in Away mode. Say, "I'm home," to switch Guard to Home mode.
At this time it is not possible to delete or disable Guard.
If you not interested in using Guard, you can disable the individual preferences in the Alexa app:
1. Go to the main menu, select "Settings," then "Guard."
2. Select the gear icon at the top right of the screen.