The certified flight instructor (CFI) was providing instruction to the student pilot, who had 3 hours of total flight time. The student pilot was practicing takeoffs and landings. During an attempted takeoff, the left skid did not lift off and the helicopter experienced a dynamic rollover, which is when the helicopter pivots about the skid remaining on the ground and enters a rolling motion that cannot be corrected with full lateral cyclic input. The helicopter rolled over on its left side and sustained substantial damage to its primary fuselage structure. The operator of the helicopter reported that at the time of the accident the student pilot had not learned how to hover. According to the company’s flight training syllabus, the CFI should not have been providing instruction in takeoffs and landings until the student pilot was able to safely hover the helicopter.