The magic in gliding comes when they keep flying only using rising air currents. However, all gliders must initially be launched high enough above the ground to have a good chance of finding this lift, or at least having a little bit of peaceful flying before returning for a landing.
The most common form of launching is to be towed up by a powered airplane. The glider and the towplane are joined together by a strong rope, which is released by the glider once the desired height is reached.
Gliders also may be launched by rapidly reeling in a long cable. This is known as winching. This has some limitations in that the cable must be quite long, and there are limitations where the drop off point will be.
Gliders may also have engines to self-launch, that are shut down, and may be retracted into the body of the aircraft once a suitable altitude is gained for soaring.