Before attempting any yoga poses, its necessary to develop awareness of your breath and relaxed breathing. Here is a breath practice that is good for complete beginners to advanced yoga practitioners.
To begin, lie on your back with your knees bent or straight. Completely release into the floor. Let go of any distractions and bring the mind inward to prepare for practice. Become aware of your body and of your breath.
Release the face, the jaws, around the mouth, the forehead and between the eyes. Let the eyes become receptive. Let the ears become receptive.
Now place your hands on your chest. Feel the chest rise and fall with the breath. Feel the collarbones as they spread apart. Feel the shoulders broaden outward. Notice the shoulder blades pressing into the floor as you breathe.
Now feel the breath as it moves your rib cage. Feel the breath in the front of your rib cage, in the sides of the rib cage, and in the back. Let the breath fill the whole rib cage.
Now bring your hands to your belly. Feel the belly expanding on the inhalations and falling on the exhalations. If you feel the opposite happening, you must stay with this exercise until you feel the belly expanding on the inhalations and falling on the exhalations. Do not force the breath, just let it move through your body. Release, relax.
Now place your hands on your hib bones. As you inhale and exhale, feel how the pelvis rocks with the breath.
Feel the breath moving through the whole body. Feel the whole body breathe. Let the body accept the breath.
Here is the exercise in audio: Enjoy!