Probably this tutorial helps you: https://www.gamedev.net/resources/_/technical/graphics-programming-and-theory/billboarded-foliage-in-unreal-engine-4-r4246 
or this one: https://www.youtube/watchttCqgpNvD0
Probably this tutorial helps you: https://www.gamedev.net/resources/_/technical/graphics-programming-and-theory/billboarded-foliage-in-unreal-engine-4-r4246
or this one: https://www.youtube/watchttCqgpNvD0