Adding custom form data to the page

I have created a from field in my admin area to have an additional piece of content for the page. What do I need to add to the page to grab this data and place it on the page? I am using the following sample code in my blueprint:

      fields:
        header.an_example_text_field:
          type: text
          label: Add a number
          default: 5
          validate:
            required: true
            type: int

just add in your template
{{ page.header.anexampletext_field }}
and it should output the content saved in the admin