To sync Calendars 5 with a Google account tap Google Calendar when launching Calendars 5 for the first time.
Then enter your Google account credentials and allow Calendars 5 access to Google Calendar events.
You can also sync Calendars 5 with your Google Calendar any time, regardless of the option you've selected at the first launch.
To do this:
All the changes applied to Calendars 5 will appear in Google Calendar in 5 sec, depending on the internet connection speed.
All the changes applied to Google calendar on the web page will appear in Calendars 5 app:
Note: Google Calendar connected directly from the application will sync events only 1 year ahead and before the current date.
If Calendars 5 does not sync with your Google Calendar account, please go to Settings>Support and tap Send feedback to send a support log to us. A detailed description of the whole situation will help us to find a solution for you.