The purpose of the Directing a Project process is for the Project Board to delegate the day-to-day management of the project to the Project Manager, providing the overall direction and management of the project lifecycle.
This process is critical for enabling the Project Manager to run the project on behalf of the Project Board within the constraints set out by them. References: PRINCE2Foundation official documentation and study materials.

The lessons log in PRINCE2 is used to record any lessons that can potentially improve future projects or stages. These lessons often originate from experiences documented in checkpoint reports, among other sources. References: PRINCE2 Foundation Handbook, Lessons Log section.

When reviewing the progress to assess the 'health' of a stage, the project manager should focus on how issues are being managed. Identifying whether issues are resolved timely or remain unmanaged is crucial for maintaining the health of the project stage and ensuring that risks do not escalate and affect the project's success.References: PRINCE27 Foundation handbook on stage management and issue resolution.

A time-driven control is defined as a monitoring system that is based on a fixed time interval, such as weekly or monthly progress reports. The expected frequency of progress reports specified in a work package represents a time-driven control, where updates are required at predefined intervals irrespective of the state of the project at those times.References: = PRINCE27 Foundation handbook and online resources

To meet the minimum requirements for applying the Change Theme in PRINCE2, it is essential to maintain detailed records of all decisions taken on issues. This documentation supports the governance of changes, ensuring that all changes and their impacts are managed transparently and effectively throughout the project.
References: PRINCE2 7 Foundation Handbook and official training materials.