"How to change everything" can refer to the book by Naomi Klein, which is a guide for young people on climate change and climate justice, or it can be interpreted as a question about making significant life or world changes. To change your life, start with reflection and goal setting, build courage, and take your next steps, while to change the world, you can get involved in movements, volunteer, donate, or make smaller daily changes like being kind and reducing your environmental impact.