Find a quiet space. Using a cushion or chair, sit up straight but not stiff; allow your head and shoulders to rest comfortably; place your hands on the tops of your legs with upper arms at your side.
Close your eyes, take a deep breath, and relax. Feel the fall and rise of your chest and the expansion and contraction of your belly. With each breath notice the coolness as it enters and the warmth as it exits. Don't control the breath but follow its natural flow.
Thoughts will try to pull your attention away from the breath. Notice them, but don't pass judgment. Gently return your focus to your breath. Some people count their breaths as a way to stay focused.
A daily practice will provide the most benefits. It can be 10 minutes per day, however, 20 minutes twice a day is often recommended for maximum benefit.