Ardha Padmasana, Half Lotus Pose
Sit in Dandasana and check which nostril you are breathing from. If it is the right nostril, bend your right knee and place your right foot on top of your left thigh with the sole facing upwards. Now bend your left knee and place your left foot under your right thigh.
You are sitting now in a half lotus pose. In a full lotus, both your fees are on the thighs and both soles face upwards. In the half lotus, one sole is facing upwards and only one foot in on your thigh.
You can sit for some minutes in this pose and then change your legs.
Ardha Padmasana is a pre-exercise for Padmasana, the complete Lotus seat. It is thus a perfect meditation pose for those who cannot reach Padmasana yet. You can also do your Pranayama exercises in this yoga pose.
It gives you more flexibility and with regular practice you can also reach the state of Padmasana.
It obviously also has several of the benefits that Padmasana has. It is a good pose for your hips, knees and ankles.
Change your legs from time to time as longer sitting in this pose can cause pain.
Focus on opening your hip and sit with straight spine.
If it is not very comfortable for you to sit in Ardha Padmasana, you can use a blanket or a block underneath your buttocks or knees to support.