The float fry is a classic fly to fish during the Autumn months when Trout are fattening themselves up for winter and a much reduced food supply but will work all year round..
Try casting it out on a longish leader (at least 8lb as the takes can be savage) and then just leave the fly alone. The floating fry works very well when there is a breeze. In these conditions let the fly drift and just keep in touch with the fly line.