Drupal 8 is still a very new system and many contributed modules are just starting to catch up.
However, there are some features already available in Drupal 8. The Calendar module is not bug-free and doesn't have all the features it did on Drupal 7, but it is working on Drupal 8.
Here's a guide to building your first Drupal 8 calendar.
Getting set up for the calendar
Finally, clear your site's cache. You can do this via Configuration > Performance.
Creating the calendar
- Go to Structure > Views.
- Click "Add view from template".
You'll now see list of pre-existing templates that you can used to create calendars.
Because you created a Date field, there should be a template available for that field. I've highlighted the template for my example. Click "Add" next to this template.
- Choose a "View Name".
- Choose a "Base View Path". This will be the URL for your calendar.
- Scroll down the preview area and you should see your new calendar:
- Click "Save".
- Click "View Month".
Visit the front of your site and you'll see your new calendar!