If you reached this page, you're booking the wrong way. DO NOT PROCEED.
You've clicked "Add to cart" instead of "Book a time". This happens when the page hasn't fully loaded.
You must be able to choose a date and time for your schedue before checking out.
To fix this, remove all the items on this cart then restart the booking process. Let the page fully load and make sure the button you clicked is labeled "Book a time".