Check out https://coderdojo.com. You don't have to invent a syllabus and approach yourself. You are better to use materials already developed and tested on young children.
Harry, in first place you must think, you are a child between these ages. What do you like? Which are your interests? The best answer, you will find with your own students. Good luck.
Google Scratch programming is good for a start. A kind of programming that captures the attention of youngsters. Gently, other ones can come in once the interest is already developed