(also known as your thesis), and focus the paper around that goal.
As a general rule, your paper needs to convince the audience of three key points: that the problem is interesting, that it is hard, and that you solved it. If any of these is missing or unclear, the paper will not be compelling. You'll also need to convince your readers that your contributions are novel. When expressing this, it may be helpful to explain why no one else thought of your approach before, and also to keep in mind how you expect the behavior of readers to change once they appreciate your contributions.
Before you write your paper, you need to understand your audience. Who will read your paper?
What are their backgrounds, motivations, interests, and beliefs? What are the key points you want a reader person to take away from your paper? Once you know the thesis and audience, you can determine what points your document should make to achieve its purpose.
For each point in your paper, you need to explain both what and why. Start with what, but don't omit why. For example, it is not enough to state how an algorithm works; you should explain why it works in that way, or why another way of solving the problem would be different. Similarly, it is not sufficient to present a figure and merely help the reader understand what the figure says. You must also ensure that reader understands the significance or implications of the figure and what parts of it are most important