All products on promotion are displayed on the Offers page.
A boiler plate (header) can be added to the Offers page via Admin > Content Management > Web Content.
Select Offer Group Page Boiler Plate in the drop down.
If there already is an Offer Group Page Boiler Plate, click Edit.
(If there is no Offer Group Page Boiler Plate, click New. )
Add / Edit content using the Editor
Click Create.
This content will now be diplayed at the top of the Offers page.
See also: WYSIWYG editor