enable Flex with files (Killing Floor 2)

Hello everyone again, yes, I already wrote that why does not flash and all that turn on, but still I did not manage to play with it, and just the other day in the Steam community I found exactly the same question and was answered by saying that I need to delve into the game files and supposedly It should work out and yes it was written by an American, maybe someone knows about this and maybe someone has tried it already please help pliz I really want to play write about this pliiiiiiiz !!!!