how do I write reflection?

It depends on the format. This is commonly done as essays, and more commonly, as journals.
Reflective writing reflects an image of you seeing the question in retrospect..how you feel, how it changed you, how it is now in context. Reflective writing is personal.

http://www.bridgewater.edu/~atrupe/ENG101/Text/Reflection.htm

To write a reflection, follow these steps:

1. Understand the purpose: Reflection writing is a way to process and analyze your thoughts, experiences, and emotions related to a specific event, topic, or situation. It helps you gain insights and learn from your experiences.

2. Choose a topic: Select a particular event, experience, or concept that you want to reflect upon. It could be something personal, academic, professional, or even a book/movie you've recently encountered.

3. Create a journal: Begin by creating a journal or document where you can record your thoughts, ideas, and reflections. This could be a physical notebook or a digital document.

4. Start with a description: Begin your reflection by describing the event or experience in detail. Provide a clear and concise overview of what happened and who was involved.

5. Express your feelings: Reflect on how the event made you feel. Explore your emotions, thoughts, and initial reactions. Be honest and open about your personal experience.

6. Analyze and evaluate: Take a step back and critically analyze the event. Consider the reasons behind your feelings and reactions. Think about the significance of the event and how it affected you.

7. Connect with prior experiences: Make connections between the event or experience you're reflecting upon and your previous knowledge, experiences, or beliefs. Explore how this new experience relates to your existing understanding of the world.

8. Identify lessons learned: Reflect on the lessons or insights you gained from the experience. What did you learn about yourself, others, or the situation? How has it impacted your beliefs or actions moving forward?

9. Consider alternative perspectives: Challenge your own assumptions and consider different viewpoints. Reflect on how others might have experienced the event differently or what their perspective could be.

10. Conclude and summarize: In the concluding part of your reflection, summarize your main points and insights. Wrap up your reflection by highlighting the significance of the experience and its impact on your personal growth.

Remember, reflective writing is subjective and personal. It allows you to express your thoughts and emotions openly. Practice, self-reflection, and feedback from others can help you improve your reflective writing skills.