Linda and Jan spend the third day reviewing the detailed requirements engineering (RE) plan and discussing the goals and boundaries of their project. They focus on understanding the motivations of stakeholders and formulating clear goals using the SMART criteria. They also create a glossary and conceptual model to ensure clear communication and understanding of key terms. Additionally, they identify and analyze stakeholders, develop a context diagram, and create initial use case diagrams to outline the functionalities of the future IT system. By the end of the day, they have a well-defined starting point for their project, including goals, terminology, stakeholders, systems, and functionalities.