In order to add a calendar section, simply drag and drop the Add to Calendar block from the Additional sections to the desired place in your page. This feature automatically creates the event in the specific calendar, when the visitor clicks on it in the email / web page.
If you want to create a description for the event when the event is created in the participants' calendar just add a description of the event in the event details.
Then the event for the participants will look like this:
