The aim of your pre-solo training is twofold. First of all, the aim is for you to understand how the glider and its controls work so that you are able to control the glider during all stages of the flight, and also to avoid and deal with any unusual situations that you could find yourself in. Secondly, the instructors aim to teach you how to fly safely. This means that you should be able to avoid any situations, which could potentially be dangerous, as well as teaching you how to recover from these. If you are making good progress and the weather is on your side you should be able to go solo after 40 to 80 flights. This is however just an estimate as some students are able to do so in less time and some need more time.
In order to understand how gliders fly and how the controls work together you will be taught how to coordinate turns, how to maintain a heading and how to launch and land a glider. The controls and their functions will be introduced to you on your first few flights. Each glider has slightly different looking controls so that it is important to familiarise yourself with these before your flight. During your briefings and your flight your instructor will first explain how these work and how to use them simultaneously. You will then learn how to maintain a heading and to turn the glider.
During your pre-solo training instructors will also aim to teach you how to soar in thermal, fly along ridges and use wave whenever there is an opportunity. This will allow you to stay up in the air rather than just coming back down and is especially important for improving your flying once you are solo. When you are able to control the glider in flight your instructors will slowly introduce you to the launches and landings and you will proceed to do more and more of these until the instructors are happy for you to do all of this on your own. However, just like being able to drive a car on a grass field doesn't mean you are safe on the road, you will at the same time receive training in other aspects of gliding to ensure you land safely back at the airfield.