GET Error

Hi All,
After some help, I am following the great beginner videos by Chris Oliver and am on Video 5, Route and route type. I have followed what Chris did in the video yet when I refresh my local host I get a Routing Error, No route matches [GET] "/about". I have gone back over the video and its exactly how Chris advised. Any help would be appreciated. Am I able to upload a screenshot on here? Regards Ben