Scrum Guide
The Product Backlog is an emergent, ordered list of what is needed to improve the product. It is the single source of work undertaken by the Scrum Team.
Product Backlog items that can be Done by the Scrum Team within one Sprint are deemed ready for selection in a Sprint Planning event. They usually acquire this degree of transparency after refining activities. Product Backlog refinement is the act of breaking down and further defining Product Backlog items into smaller more precise items. This is an ongoing activity to add details, such as a description, order, and size. Attributes often vary with the domain of work.
The Developers who will be doing the work are responsible for the sizing. The Product Owner may influence the Developers by helping them understand and select trade-offs.

Scrum Guide
They are fixed length events of one month or less to create consistency. A new Sprint starts immediately after the conclusion of the previous Sprint.

A Business Model Canvas is a technique that helps to visualize business models. An organization's business model can be described with 9 basic building blocks.
Product Box is also an appropriate technique to create the vision, share it with the Scrum Team and stakeholders.
This technique involves a number of stakeholders from across the organization, including users.
- It helps prioritize functionalities and requirements, and reach a consensus on the most important benefits and features offered
- Because it is a customer-oriented technique, it gives the team the opportunity to learn what the users want from the product
For this answer, observe that techniques and examples that go beyond the Scrum guide is described in order to sustain the answer, in case you have experience with specific techniques, use them.