This tutorial will show you how to add a horizontal menu below the header area in Confluence using ThemeBuilder.
Create a new custom panel called 'menu'
In the 'header' panel, after all other code, add the 'include panel' macro to import the new 'menu' panel.
Edit the 'menu' panel and add this code to form the base for your menu:
This should give you a horizontal link menu that displays just below the page header, as show in the first image above.