Landscape grass not showing

I want grass type like this video Quick Unreal Engine 4 Grass Tutorial - YouTube
But its not working. Here is some screenshoot

Let’s see.
You have probably figured it out.

It may be that your layer names do not match.
‘grass’ vs ‘Grass’

Or I have had the issue where I am using world composition and in a test map, the grass type works.
But in the world composition map, it does not. I have to recreate the material layers for each map to ‘force’ UE4
to re compute the materials on each map.

Добрый день, я думаю, что проблема в Sample “Grass”.
Там нужно будет поставить Preview Weight “1”

I think I found the solution: