To use the Maxwell scatter extension in Maya, select one or more polygon meshes and click on the 
shelf button. This will attach one scatter node to each of the meshes. The scatter nodes generate blades on the surface of their base meshes in order to preview the final position and orientation of the scattered meshes.
The only Maya-specific attribute for the scatter node is the "Scattered Mesh" parameter which is used to select the Maya mesh to be scattered on the surface of the base mesh. All the other parameters are explained on this page of the main Maxwell manual.