When editing a blueprint, you can add some instructional text, as explained in the documentation:

Customising this blueprint

You can customise the templates that are used by the Decisions blueprint - see Customising the blueprint templates.

You might choose to edit the index page in a space to change the columns to be displayed by the Page Properties Report macro.

You might choose to edit the page template to add some headings or instructional text to the background section, or even add rows to the Page Properties macro, for example a row for the date the decision was made.

To find out more about using instructional text in a template see - Instructional text.

Instructional text is not displayed when creating a page using that blueprint.