The yaw is controlled by the swept wing design of the glider. As a hang glider flies, it sinks through the air. If that air is rising faster than the glider sinks, the glider goes up. This rising air is called lift. Without lift a hang glider sinks at about 150 feet a minute, so it depends on how high you are.
Most pilots like to fly in lift.
A normal flight in good thermalling conditions will last about 2 or 3 hours. With good lift a pilot can fly over 100 miles using her wit and skill. Flights exceeding 300 miles have been recorded. To foot launch on a slope you hold the glider in the proper position, and smoothly accelerate the glider to a run. When you reach the proper air speed the glider will lift you off the ground.