The confirmation will show the text relevant to the selected participation type for your participant categories. If you wish to change the participation types, you can read more here.
In the preview of the confirmation, all participation types will always be shown, regardless of what has been selected. This happens because the selected participation type is only associated with the confirmation once there is an actual registration. Similarly, merge fields like first name, last name, choices, any prices, and order lines will only appear in a real confirmation.
To see a real confirmation, you can try registering for your own event and view the confirmation that will be sent.
Read more about the location on the confirmation here.
