The drain outlets will be under the cowl cover. Both wiper arms need to be removed (14mm nuts) and then the cowl cover (push clips), and then to reach the driver's side drain you'll also need to unbolt the wiper gear/motor assembly (10mm screws). The drains can be reached from inside the car instead, but on a gen1 Rogue I don't recommend it. It's a giant PITA, and popping the cowl cover is easier. Once you get to the drain fittings, use a hook tool or sharp nippers to remove the little "disc" in the center of each fitting. Those are the primary reason the drains stop up.