What were they trained to do, were they members of the paratroopers or real pilots, or infantry? Were they volunteers or failures from flight school? Were they trained to fly or just land? What did they do after they landed during a battle? Were they evacuated from the battle? Bomber crews flew 25 missions, how many missions did the glider pilots have to "fly?" What was their survival rate?
The Glider Pilot Regiment was a collaboration between the RAF and the British Army. Pilots were recruited from volunteers for the Airlanding Brigades, but were passed for training and then trained by the RAF. This was due to a dispute between the Army and RAF, who both viewed the pilots as passing under their jurisdiction. The RAF viewed gliders as aircraft and argued that therefore they came under their jurisdiction; the Army argued that as the glider pilots would subsequently be fighting upon landing they should be under Army control.
After six weeks testing at the GPR Depot at Tilshead, they spent twelve weeks at one of four Elementary Flying Training Schools, which left them qualified as a trainee light aircraft pilot. Pilots then went on to a twelve week course at a Glider Training School where they trained with the GAL.48 Hotspur and finally a six week course training with the Airspeed AS.51 Horsa with the Heavy Glider Conversion Unit. During this training the pilots would learn to fly light aircraft but it mainly constituted teaching them how to control the gliders while they were being towed and the difficult task of landing them.
Upon landing they were under orders to stay back from the most intense fighting and act as support soldiers. Upon relief they were quickly escorted behind lines.
The gliders were designed and piloted with the intention of crash landings and the landing sites were chosen based on their suitability for landings. Pilots were often thrown out of the cockpit, suffering injuries as a result of this, but they were rarely killed in the landing. In a successful landing there were usually minor injuries. The greatest danger lay in reaching the target. Horsa gliders were designed to be as lightweight as possible, and so were not provided with any armour. This made them particularly vulnerable to flak. There was also the danger of being released too early. In Operation Ladbroke, 65 gliders were released too early and they crashed into the sea, claiming the lives of around 252 men.
EDIT I: Tried to answer /u/GreenStrong's question
EDIT II: Corrected details on pilots' combat role