Hi, your landscape settings will depend on the size of the height maps you import.
If you import a series of 10091009 tiles, then each sub levels will be 1km1km; and if you import a series of 40334033 tiles, your sub levels will be 4km4km. When you import your tiles, you cannot change the size of your component because the size depends on the tile size you import, but you can change the way it will handle the landscape creation, 22 sections or 11 sections, that will change the number of quads and component that will be created for your tile (Which stays the same size because it depends on the resolution of the tile).
You are the master of your world size by being the master of your maps size that you import.