Manual Painting
Each Errant Landscape Stamp Brush can have multiple stamp or falloff texture which together modify the landscape. These textures can be adjusted/tweaked to fit your specific needs. For example, you can create mountain range texture by arranging existing mountain textures.
Hand Painting a Stamp Brush's Texture
To begin painting on a Stamp Brush's textures, select one of them in the "Manual" tool.
Then click on the affected landscape region to start modifying the texture.
To finalize the texture changes, press save and decide if you want to overwrite the original texture or create a new texture asset.
New texture assets are placed next to the brush's map asset under the ProceduralWorldGeneration directory.
You can change the painting brush settings (hardness, shape, value, blending mode etc.)
Visualization can also be adjusted (color, height, opacity or minimal visualized value).
Controlling where and how a Brush affects the landscape
To control this, select and paint on a Falloff Texture from the outliner.