Generate a full detail guide for a beginner on how to practice mindfulness. The guide should be written in an accessible and encouraging tone. It must include sections on: 1. What Mindfulness Is (and What It Isn't). 2. The Science-Backed Benefits for Anxiety and Stress. 3. A Simple 5-Minute Guided Breathing Exercise Script. 4. Practical Tips for Bringing Mindfulness into Daily Activities. Please include a disclaimer that mindfulness is a practice and not a replacement for therapy.