Step 1: Click on the Websites tab
Step 2: Identify the property you wish to edit under the single or multiple property section and select Website Option
Step 3: Navigate to Pages
Step 4: Once in Website Pages, select the Edit button next to any active page
Step 5: By selecting Edit, you will be launched into the advanced page editor. From the advanced page editor, you will have the ability to add your external link. To do so, hover over your header navigation and click the green Settings button.
Step 6: Upon clicking, Header Navigation Settings will appear. You will then want to add the External Link component from the right hand navigation.
Step 7: Drag the External Link component into the active navigation table.
Navigation placement shown in Header Navigation Settings will mirror the placement on your live site.
Step 8: Select the External Link the Click To Edit button
Step 9: An edit field will appear below the External Link navigation bar which will allow you to specify the Navigation Text and External URL.
Step 10: Select the Save Settings button to see the updates to your header navigation.
Step 11: If you are satisfied with your changes, select Save Page button in the left hand menu.