If you allow access to your calendar, you will be able to add municipal events directly to the calendar on your device.
To add an event, click on the event in the calendar, and click on the icon representing a calendar with a plus and a person. The event will automatically be added to your personal calendar. To remove it, just click on this icon again.
Can’t sync the app to your device’s calendar?
This is probably because you denied access when you first opened the app. Go to your device settings and in the privacy properties, make sure that access to your calendar is allowed for Voilà app.