I have started to read the Scrum Guide which is a sixteen-page long document in which is explained the principals of Scrum.
First of all, Scrum is not a set of guidelines which you’re tightly coupled to, but it’s a framework that tries to drive the teams to follow some rules and advices such as:
The Scrum framework consists of Scrum Teams and their associated roles, events, artifacts and rules. Each component within the framework serves a specific purpose and is essential to Scrum’s success and usage.
The Scrum Team consists of a group of between three and nine members. There’re some roles that are mandatory like Product Owner, the Development Team and Scrum Master.
The Product Owner is responsible for managing the Product Backlog, which is a list of items (PBI) or user stories that need to be completed to finish the project. A user story can be thought as some kind of use case but with some differences.
The PBIs are ordered by priority which is meant to be used to reflect how important or urgent a piece of work is for the project. The only person responsible for assigning priorities is the Product Owner. These priorities are likely to change along the time. However as soon as the dev team starts to work on a subset of PBIs (this is called Sprint Backlog) no one should change them. Everyone in a organization has to be able to access the Product Backlog but without changing it.
Regarding the Sprint Backlog, the best way to make it visible to the whole organization is by using a whiteboard and post-its or stickers.
How to decide how many of the top priority PBIs of the Product Backlog are going to make up the Sprint Backlog will depend on how difficult or complex each of the PBIs are. In other words, every PBI has a number of points to reflect the amount of effort that the dev team will have to put on it to implement it.by