Well, first you need to understand the layout and dimensions of your comic book. Then, use graphic design software like Adobe Illustrator or Photoshop to create the template. Pay attention to the margins and bleed areas for a professional look.
One grade 4 brain bleed story could be about a young athlete. He was playing a very rough sport when he suddenly got hit hard on the head. At first, he just felt a bit dizzy but then he started having severe headaches. Later, it was found that he had a grade 4 brain bleed. The doctors had to perform emergency surgery to relieve the pressure in his brain.
I'm not sure specifically which 'bleed for this real story' you are referring to. It could be a movie, a book, or some other form of media. There's not enough information to give a detailed account.
A bleed graphic novel often has panels where the art extends to the edge of the page. This gives a sense of a more immersive and continuous world. It can make the action seem more immediate and intense.