A short demonstration of the manual extension of the nose landing gear on a Boeing 737NG. In the cockpit the pilot pulls the handle and the nosegear unlocks from its up position, then falling by gravity and in flight helped by the drag, it ends up in the down and locked position.

When the cockpitfloor access panel to the handles is opened, a switch activates and the landing gear selector valve goes in a bypass mode. This prevents any hydraulic pressure to go the the landing gears. So the landing gear lever may still be in up, the gear comes down pressureless.