The previews are rendered at the highest quality with all settings maxed out to showcase the product. Also the shader displacement will look much better if it's enabled (Cycles only) and subdivisions are very high. This brings out a noticeable difference in how the terrain looks. 

The grass instancers are a seperate node setup in the modifier panel below the AutoTerrainer. They are disabled by default in the viewport so as to not bring the performance down of anyone opening the file for the first time, not everyone has the same hardware configuration afterall. You can turn these on individually and play with the values for a better result.

Auto-Terrainer is compatible with Blender 4.0.2 and up.

THIS IS NOT AN ADD-ON !

You don't have to install anything, simply save the file(s) in a desirable easy to access location. This is a demo blend file containing the nodegroups. You can either mark the terrainer as an asset and use it from the asset browser to customize it to your needs or you can simply append the terrainer into your blend file. 

PRO version will include higher quality textures and a larger variation of foliage options. 

There will also be CINEMA versions in the future that will provide production ready assets and support.

Functionally all versions make use of the the same base nodegroup and material setup, each biome is pre-customized to that specific terrain by myself, this may include some additional features like new textures, foliage unique to that biome, custom tools, etc. 

If you want to tinker around and make your own biomes, the terrainer is fully customisable and easy to tinker with. I highly encourage you get into the node editors and play around it to make your own unique variations.