This is very important.
If you are using a low spec. PC like me, and you have issues on the Grass part
On the Engine Scalability Settings, always set the Foliage to Medium, otherwise you will never get the grass clumps
Also, when you are importing the “SM_GrassClump” & “T_GrassClump” Uncheck the “Generate Missing Collision” Box.
For some reason, I get this box checked by default which makes the “SM_GrassClump” to not work properly.