Making grass!

Hi guys!

Im pretty new in Blender. Im learning it for a month now through tutorials, and now I want to make plants, like grass, flowers and so on… Basicly what Im trying to say is that I want to make my own grass essentials! But I dont know how to do it if im planning to use it in the future in a game engine (unreal engine4). I saw a lot of tutorial on youtube but I dont know if they are good for games or just for scenes in Blender. So can you please tell me how to model plant that is “game ready”? Because I dont want to make it very low poly. Any answers are much appriciated! Oh, and im 17 so sorry for my grammar being shit.