Google home & hub likely refers to the calendar for your Google account
(https://calendar.google.com/calendar/u/0/r?pli=1)In the calendar
settings via a web page, (cog next to profile pic) you can set the time
zone, daylight saving options etc but sa...
Just a guess, but you do have to actually set up a home / away routine
first via the Automation screen.Once a routine is active, Presence
Sensing then becomes an option?.