The purpose of the 'Organizing' practice within PRINCE2 is to establish and define the project management team structure and responsibilities. This includes specifying roles and responsibilities for managing, delivering, and overseeing the project effectively. The organization theme supports project success by ensuring clear definition and communication of who is responsible for various project activities.
PRINCE2 7 Foundation guide and official PRINCE2 documentation on organizing practices.

Uncertainty in a project is identified, assessed, and controlled through the application of the 'Risk Management Practice' in PRINCE2. This practice involves systematic risk identification, assessment, and response planning to manage project risks effectively and ensure that they are within acceptable tolerance levels.References: = PRINCE2 7 Foundation Training Manual and official PRINCE2 website documentation

PRINCE2 recommends three levels of planning (Project Plan, Stage Plan, Team Plan) to reflect the needs of different levels of management involved in a project. Each plan serves a specific management purpose and addresses the needs of different management levels within the project. References: PRINCE2 Foundation official documentation and study materials.