Beginner level: sit in a chair and breathe slowly. Focus on the sensation of your breathing, feeling the air go in and out. If any intrusive thoughts creep in, try to revert back to focusing on your breathing. Meditation looks passive from the outside, but it is a cognitively active process that takes practice to achieve, just like drawing or programming or anything else you want to do. It's the art of placing your attention somewhere and keeping it there, not letting your thoughts carry you away.