When I install addon scenery it seems to work only half the time, what is the key to it?

I had posted this to the wrong sim but since have found the lesson on ADDON SCENERY. it states 2 ways of doing it. I think I have tried each one but still
seems to have too many not really work. Is one more fail safe thenthe other. I always get confused if you have to open the scenery and texture and copy and paste them into the scenery /texture folders in ADDON SCENERY and then just the title of the scenery just copy and paste into ADDON SCENERY?

any help or sugestions would be greatly appreciated.

Sterk03