Principles of First Aid outlines the role and responsibilities of a first aider. The three aims of first aid are to preserve life, prevent worsening, and promote recovery. A first aider must first ensure the safety of the situation and not endanger themselves or others. Their role is to provide initial care until emergency medical help arrives through actions like controlling bleeding, treating for shock, and calling for an ambulance. A first aider must protect the casualty's privacy and document their care provided. They should be aware of potential environmental and human dangers at the scene like broken glass or risk of infection from bodily fluids.