Hello Andreas,

To add a link to Terms & Conditions, you can use "Checkbox" or "Radio" custom fields. In the custom field you need to add an anchor tag like this:

<a href="https://wpamelia.com/terms-and-conditions/" target="_blank">Terms & Conditions</a>

So this text appears as a hyperlink that opens a new tab (target="_blank") and takes the customers to your Terms & Conditions without them leaving the booking form. So the custom field on the back end would look like this:

As you can see, we made this radio button a mandatory field, so no one can book an appointment without checking the "I agree" button.