Presolo
You learn to control the airplane. Straight and level, climbs, descents, turns, slow flight, stalls, ground reference maneuvers, and above all takeoffs and landings, over and over. You learn radio work, which in the Los Angeles area means talking to a control tower from your first lesson. You cover the presolo written exam and the airplane's systems and limitations.
Ends with your first solo, usually between 15 and 25 hours depending on how often you fly. Before that solo you need the piece of paper that goes with it: the FAA student pilot certificate.