Stand with shoulder width or narrower stance on elevated platform with thigh against bar. Grasp bar with shoulder width or slightly wider overhand grip. Disengage bar by rotating bar back.
With knees straight, lower bar toward top of feet by bending hips. After hips can no longer flex, bend waist as bar approaches top of feet. Lift bar by extending waist and hip until standing upright. Pull shoulders back slightly if rounded. Repeat.
Begin with very light weight and add additional weight gradually to allow lower back adequate adaptation. Throughout lift, keep arms and knees straight. Do not pause or bounce at bottom of lift. Do not lower weight beyond mild stretch throughout hamstrings and low back. Full range of motion will vary from person to person. Those with less flexibility may not even need to stand on platform. See Dangerous Exercise Essay. Also see Stiff Leg Deadlift.