If you have several calendars on your website and want to have the same events on all of them, the Calendar sync function is what you need. This function will let you sync all the calendars on your website and manage them as one calendar.
To sync your Calendars, please:
Double-click on the calendar to open the Settings.
Click on the Add-ons section.
Open Add-ons Store.
Add To Site the Boom add-on.
Once Boom add-on is added, click on Boom from Add-ons section.
Click Enable synchronization
From the list you can choose the calendars to sync with.
Moreover, by clicking on the > icon, you can select categories or events to sync.