Parameters

You may pass various kinds of inputs to the material masks (such as landscape weightmaps, hand-painted masks, growth of other species, etc) and then combine these inputs with procedural logic. You can even add your input classes.

Most of the time you can just use Biomes input nodes instead of using parameters.

Those inputs are then accessible inside the material as textures, vectors or other types of data. The Parameter Name property of each input specifies the name under which that parameter is accessible inside the material (as a TextureSampleParameter2D for example).

Read the parameter class tooltip to learn what type it is using

Component Location is a Vector while Landscape Weightmap is a Texture.

For texture parameters it's best to set the MaskFallback texture from the Biomes plugin as the default texture.

Instance Parameters

To control parameters like in normal material instances you can add the Instance Parameters class to your list of parameters.

There you can map values to the names of those parameters.