Outlines are important to most writers. They form a road map and become a guide for the author. You can use an outline to stay on track while still exploring the depths of creativity. And, most often, this outline takes the form of a story arc outline. But what if you know exactly how many chapters you were going to have? I knew I'd have forty chapters, plus a prologue and an epilogue, when writing Dragon's Tempest and Thief's Heartache. I'd already established that the first book in The Imperial Series that the books would all have forty chapters. So a chapter-by-chapter outline would be the best decision for any book in this series.
To create a chapter-by-chapter outline, you'll have to have a general idea of what your story will be. Then you'll have to get specific. List your chapters and leave plenty of space to add details. Once you've decided how many chapters you're going to have, start filling in the details.
List each chapter's plot point, making sure you have an inciting incident within the first few chapters. Ensure you have enough chapters to successfully weave your way through the rising action and into your crisis, climax, and resolution. Remember that your crisis, climax, and resolution can either happen in a single chapter or over several. The choice is yours and should fit the particular book.
Now look back at each chapter and tweak them. Treat each chapter like a mini-novel. They should have a beginning and end and something (rising action) need to happen in between. Don't let any chapters exist simply because you told yourself you'd have forty chapters (or twenty, or whatever number you came up with). Don't be afraid to merge chapters or even cut whole sections during the outlining process.
A chapter-by-chapter outline is only a guide. It's not set in stone. Make sure you allow your outline to stay fluid. Never lock yourself in simply for the sake of your outline.