The empathy map is a tool to help understand customers at a deeper level beyond demographics. It involves charting a customer's environment, behavior, concerns, and aspirations. To use it, identify key customer segments and select one for profiling. Name the customer and provide demographic details. Then make notes in the empathy map diagram about what the customer sees, hears, thinks and feels, says and does, pains, and gains. This helps develop a holistic understanding of the customer from their perspective.