In default, click a Gem's Template, it just apply the template styles, and don't insert the text in template.
To enable insert the template with its text:
Click "Edit" tab -> "Template" menu -> "Manage Template" menu item -> in "Manage Template" window, check the "Apply with Template Text".
Apply Gem's Cornell Note New Template
After check "Apply with Template Text".
Create new a OneNote page, then click "Edit" tab -> "Template" menu -> "Cornell Note" template.
It will insert the Cornell Note with <<Date>> field into this page.
Click "Cooperation" tab -> "Outlook" group -> "Field" menu -> "Convert Fields to Result" menu item.
It will replace all fields in this page with results.
From this example, you can create Gem's Template with fields, and apply this template, use "Convert Fields to Result" feature to replace the fields with results.
Create OneNote Gem Template, Apply Template to Current Editing Page.
Field include: Year, Month Name, Day Name, Date, Date and Time, Date and Time (UTC), Local Time Zone Name.
Demonstration