@TheReader202dl You might start by asking yourself questions, such as “Where does it take place? At what time?” Then you can review your character "Who is he and what can he do?” remember to give your main character a background. From there you continue with the objective that your protagonist has, which is what he seeks and justifies it.
Once you are clear about what you want to achieve, you start with the conflicts or obstacles that the protagonist must overcome. This must be made as clear as possible, so that the Fanfic is not too short.
When you are nearing the end of the story, be clear about how you achieved a victory. Depending on what you choose, your story can end in a happy ending, a more real one or a catastrophe.
When you are going to write the first chapters, try to include the first points, without them breaking pieces, so that the reader can understand what is happening and make it easier. When you need the conflict, try to spread it, always describing new places or characters.
That is what I am using for my stories that I have in progress, maybe this method will work for you.
