There are different ways to find the sceneries in Flight-Sim.org:
(1) Overview map "Aerofly FS2 Scenery-Map":
With a click on a green marked country in the overview map the category of the country opens.
In this country category the individual contributions can then be selected.
(2) Categories in the menu "Filebase":
With a click on "Filebase" the overview of the categories opens.
Another click on "addons/scenery/..." opens the list of categories for the countries.
You can then select the individual contributions in the individual country categories.