It is usually just dropping the scenery folder in the community folder (maybe you need to extract the scenery first). The correct folder is the one containing the layout.json and manifest.json files. If the scenery needs additional folders, like asset packs and so on, they usually just go alongside the scenery in a seperate folder within the community folder. The assert pack folder also should include the layout and manifest files.
To give mor eleborate help we need to know which scenery you are talking about and where you purchased or downloaded it.