The dev team keeps getting yanked around and interrupted. So every two weeks you get all the business people in a room and you have them make a list of things that the dev team will work on this cycle. Then the dev team can execute in peace. The Scrum Master's job is to protect the dev team. The Product Owner's job is to get the business people to converge on the prioritized list of work.
In a healthy organization, Scrum is much less useful. Scrum combines three different cycles: defining work, executing work, and reviewing work. In a flow-based process like Kanban, you can split them up.
The product manager builds a prioritized backlog of work, and the dev team estimates tasks to help do business ROI calculations. It's a collaboration between product and development.
The dev team implements tasks from the backlog one by one. You can batch up work to make a release, deliver incrementally, or use tools like feature flags. You evaluate whether features are effective working based on metrics.