Help to add scenaries

Guys, I downloaded about 20 Mb of scenaries with my old 56k modem, and now am not be able to make them function properly. 
The fact is that when I specify the directory in which the scenary folder is contained, after naming it, by clicking OK the window of "specify directory" comes out again. It looks like it doesn't accept the directory.
I still have to understand where in the hell the file .bgl have to be put, if in a folder, and then putting this one in the "addon scenary" directory or simply in the "scenary" directory. Then, is the folder that must be specified/activated or the .bgl file
?
Thanks very much for help
Giovanni (Italy)

The fact is that when I specify the directory in which the scenary folder is contained, after naming it, by clicking OK the window of "specify directory" comes out again. It looks like it doesn't accept the directory.

I still have to understand where in the hell the file .bgl have to be put, if in a folder, and then putting this one in the "addon scenary" directory or simply in the "scenary" directory. Then, is the folder that must be specified/activated or the .bgl file

Thanks very much for help
Giovanni (Italy)