One of the most basic yoga postures of all is the Sukhasana, which is considered as being one of the most basic and easiest yoga postures of all, and it is a starting position which helps you to focus on awareness of your breathing and your body and as well helps to strength back muscles and to open the groin and hips.
In order to complete this position you need to sit cross-legged with your hands on your knees, and focus on your breath. Make sure that you keep your spine straight and push the sit bones down into the floor. Allow the knees to gently lower, and remember that if the knees rise above your hips, you need to sit on a cushion or block in order to fix this.
Another one of the most basic or beginning postures is known as the Dog and Cat, and this one works primarily to increase the flexibility of the spine. It is really two poses, one flowing into the other. You begin on your hands and knees, keeping your hands just in front of your shoulders, with your legs about hip width apart.
Then, as you inhale, tilt the tailbone and pelvis up, and then let the spine curve downward, dropping the stomach low, and then lift your head up. Stretch gently, and as you exhale, move into the cat position by reversing the spinal bend, tilting the pelvis downward, and drawing the spine up and the stomach in.
There are so many other yoga positions however you want to start with these and the other most basic and easy positions first, so that you can start here and then work your way up as you increase in talent and flexibility.
Remember that yoga is one of the best exercises that you can do by far, and so you should definitely try it out for yourself, at least once, just to get a feel for it and you are surely going to fall in love with it.