Hi sorry guys I’m new at unreal engine 4 start learning and I watch some tutorail about dynamic Day Night Cycle and wind effect at digital Tutor.I’m kind have this trouble in my scene you can see it in the picture I upload the (Green,white,Yellow Square). and I don’t know why I know it’s stupid question.
I think you mean the lens flare -> you can disabled it in the post process settings 
There you can also change the shape of it