This web site is now controlled by a tree menu over on the left side. If there is a + sign next to a folder, then you can click that + sign, (or on the folder name itself) to expand it. If you click it again, it will collapse.
The photo slideshow has its own help page. While viewing the Slideshow Gallery (table of contents) simply click on the one named "Slideshow Tips" to view it.
You can close this box by clicking anywhere outside of it.