It's natural to sit on a stool with your legs upright. Put your hands on your thighs, keep your eyes and mouth closed, and don't be rough in your ears and breathing. Keep Guanyuan point (under navel and abdomen) for more than an hour at a time, and practice when you have time. Generally speaking, I feel it in an hour.
Laozi said that a wise man will strictly enforce the law of keeping in good health when he knows it, while a fool will only admire it when he knows it, but he doesn't know how easy it is, so it is difficult for him to stick to it.