Directory Help

I am pretty new to FS 9 and here is my problem. I feel like my FS 9 directory structure is all over the place. I have add-on scenery in the /addonscenery file as well as the /scenery/world file. Now I'm looking at things that need a Landclass folder (with no texture folder) LOL
Where are all these things really supposed to go? Where are all the afcads supposed to be? How about the flight plans themselvs? It seems as if I am seeing them everywhere:)
Any help or insight or a direction would really be helpful. Thanks!
Where are all these things really supposed to go? Where are all the afcads supposed to be? How about the flight plans themselvs? It seems as if I am seeing them everywhere:)
Any help or insight or a direction would really be helpful. Thanks!