There are two ways and either way works well:
- Write the scene as a prologue instead of as a chapter. It’s done all the time and it works great. The only thing to remember if you use this technique is not to make the prologue too long because, for some reason, readers are turned off by a really long prologue and will simply skip it and get to the book itself. Even if the prologue is essential to the story and you do your best to make sure the reader understands that fact, they still tend to skip it if it’s too long.
- Write the first chapter as a ‘flashback.’ This is usually done by using the first paragraph to set the scene that the present/real action is in and to kick-start the flashback. Then the last paragraph in the chapter brings the reader back to the present.