To link a tab directly to a page:
Clear the Content Area of any data.
Select the tab.
Link the tab using the Hyperlinks panel.

To create a tab for a submenu for alike pages:
Select the grey plus box at the end of the Accordion.
Name and style the parent tab to coordinate with the rest of your menu.
Select the grey box at the end of the menu to create however many submenus you need within that Accordion.

Note: Before publishing your site, be sure to collapse all submenus of the Accordion so users view your menu collapse upon loading.