Hang Gliding training usually begins on a small hill. You start at the bottom and just learn to run with the glider. As your skills progress, you gradually work your way up the hill gaining more airtime the high up on the hill you launch from. All of this is done with an instructor at your side.
Here is a video of a few Training hill flights at Andy Jackson Airpark, San Bernardino California:
At Lookout Mountain Flight Park in Trenton, Georgia, there are two training hills. Clearing the first (small) hill is an indicator that you have achieved your H1 rating as a pilot. You must launch aggressively, fly straight and land on your feet four times in a row to clear the small hill. On the big hill, you will perform a series of tasks to learn and prove you have learned how to control the glider in flight. Strong launches and landings continue to be necessary. Successfully clearing the big hill is synonymous with achieving your H2 pilot rating. It also indicates you are ready to fly from the mountain.