Stand tall, fold over, let your hammies lengthen.
Hinge from the hips and let your head and neck go heavy, don't force the reach.
Folding forward from the hips lets gravity do the stretching, lengthening the hamstrings while the weight of your hanging head and arms gently decompresses the whole back line. Because it is a relaxed hold rather than an active pull, it works as a nervous-system downshift as much as a stretch. It slots in after leg sessions, long days of sitting, or anywhere you need the back of your body to let go.
Keep a soft bend, especially early on. Locked knees push the stretch into the wrong tissues and encourage your lower back to round hard, while a slight bend keeps the stretch in the hamstrings where it belongs.
Not at all, reach range is irrelevant. Hinge from the hips, hold your shins if that is where your hands land, and let gravity work. Consistency moves your hands down over weeks, forcing it just makes you strain.
Thirty seconds to a minute of relaxed breathing works well, longer if it feels good. Come up slowly when you finish, rolling up through the spine, since standing up fast from a deep fold can leave you light-headed.
