if you want data to be available in the emails (for example) you’ll have to add a/that checkbox to the main formfields instead before going to the confirmation page.

the confirmation page checkboxes are there to – for example – stop people submitting an order unless they have accepted the T&C’s (or similar) if it was made required (or whatever else you want to do with the options there)

did you enable that checkbox (whatever you named it ) to be used in the templates ?