The Product Backlog is only useful when it is kept in good shape. In Scrum it is an emergent, ordered list of what is needed to improve the product, and the Product Owner is accountable for managing it. Keeping it healthy is an ongoing job, not a one-off task, and it is a large part of how a Scrum Master helps the Product Owner and the team.
You'll start with Product Backlog refinement, the ongoing activity of breaking items down and adding detail, and why communication matters so much while doing it. Then you'll look at who should be involved, and at examples of poor and great refinement. After that you'll see why the Product Backlog is not only made of user stories and why it is ordered rather than simply prioritized, and which factors can influence that order.
With a well-managed backlog in place, you'll be ready for the next module, Estimation & Sprint Planning, where the Developers size items and turn the top of the backlog into a plan for the Sprint.
What Product Backlog refinement is, how it prepares items for Sprint Planning, and why communication is central to doing it well.
Who takes part in refinement, and how the Product Owner, the Developers, and others contribute to the work.
Contrasting examples of refinement that works against the team and refinement that helps it, so you can recognize both in practice.
Two common misconceptions about the Product Backlog: that it contains only user stories, and that it is prioritized. Also covers how its order reflects the Product Owner's vision for the product.