Do you have to sit cross-legged on the floor to meditate?

Not at all. You can meditate sitting in a chair, lying down, standing, or even walking. What matters is a position that is comfortable and lets you stay reasonably alert, not a particular posture. The cross-legged image is just tradition and photos, not a requirement. Choose whatever your body is happy to hold for a little while. StillMind works in any position, so you can practise on the sofa, in bed, or at your desk.