Thankfully, you don't need to sit cross- legged or contort yourself into the lotus position to meditate! Comfort is key, so sitting comfortably in a chair is fine too. Place your feet flat on the floor and hip distance apart. Don't lean back on the chair but subtly lift through the crown of your head to gently lengthen your spine. Palms can face down on your thighs or you may prefer to rest your hands loosely in your lap. Your eyes can be closed to help you focus on the body and breath, but if you are feeling sleepy then keep your eyes open in a soft gaze (pick a point on the floor a couple of feet ahead but try not focusing on anything in particular)
Take a few moments to focus on your body and settle into the stillness you have created. Become aware of the sensations you can feel as your body makes contact with the chair, your feet on the floor and the weight of your hands in your lap. Perhaps you can sense the temperature or the feeling of your clothing against your skin. Whenever your mind becomes distracted and pulled away to thinking mode (which it will!), simply acknowledge it without judgement and gently guide your attention back to what you can feel in your body.
Gradually allow yourself to become aware of your breathing. Breathing is automatic and our bodies know exactly what to do. You don't need to change your breath in any way, just notice the coming and going of each breath and how this feels in your body. You may have a general sense of expansion and contraction or you may be able to feel more subtle sensations such as the air passing through your nostrils or mouth. Try to stay with these sensations for a few moments. Again, whenever you notice your mind wandering, gently escort your attention back to the awareness of breathing. This is meditation!