After that initial hook, you can now try to help your reader to understand what's going on. This is a time when you can give the background. Why was there such a commotion in the first scene? What made you write that explosive sentence?
When you give the background, it's when you explain some information to your readers in order to 'reel them in' - once you've 'hooked' them. Just be careful not to explain too much. Give your explanations gradually, interspersed throughout your work. Try to find creative ways to give background other than through narrative. Include background in dialogues, scenic descriptions, anecdotes, character descriptions, and/or historic information.
Creative Writing Project to Consider: *Look at your manuscript. Read the first few sentences. What do you think is the background for what you've written? For example, can you explain why your character is so angry/sad/happy to start with?
*Some background ideas that you might want to think about: motivation, reasons/rationale, and personal history.
*Other than narrative, try to re-write your background in a different way (dialogue, scenic desciption, etc.)