If you want to adjust the volume on your Google home page, you can simply swipe on the touch top of the device to increase or decrease the volume. However, alarms use a different volume level. To set this up, you need to open the Google Home app on your phone.
Alarm volume is a separate setting in Google Home because apparently you don’t want to miss your alarms just because you turned off your music. If you need to adjust the volume of your alarms, open the Google Home app and tap the Devices button in the top right corner.
Scroll down to find your Google Home in the device list. Press the three-dot menu button and select Settings.