Here are some steps that can help you write a comic book:
1. Pick a character: Who is your story about? Is your character a human or a fierce lion?
2. Sketch your character: Do a few sketches of your character on scratch paper. Draw him/her happy, sad, and angry. What does he/she look like running or jumping? Make quick sketches of your character doing different things.
3. Think of a plot: What does your character want? What is the conflict in the story?
4. Plan your panels: Before you start drawing, plan how your story will go by saying it out loud.
5. Bring your comic to life! Draw the panels and add speech bubbles and captions.
Here's a link to an article that explains these steps in more detail . You can also check out this article for more information on how to make comics for kids.