I'm not quite sure about what you mean by layout design of the level scenes, but currently the asset has enough tiles and props to fully decorate an forest scenario. Also you can expand the Z-axis as much as you like with the recent update of ramps and stairs, as long with cave entrances and dirt roads, which can lead to dungeons and other locations.
The level design itself is up to whatever the dev wants it to be, but you can find an .ase file inside the asset who serves as a sort of mockup on how you could organize the different layers and objects inside the scene.