To change elements on the home page, you must change them at the source.
The new main navigation [drop-down] is controlled by the main folders with the folder check-box engaged to show it as a navigation structure [green globe-like icon].
The new gallery images are controlled by images in a folder in the "IMAGE CENTER".
The new quick links are controlled by a page in the home page folder called "02_Quick Links/Buttons". Simply add another bullet and hyperlink it.
If you need help, contact firstname.lastname@example.org