The affinity diagram is a creative process used for gathering and organizing large amounts of datas, ideas and insights by evidencing their natural correlations.
It starts with a statement of the problem or the goal.
During the first session each participant should think of ideas and write them on small pieces of paper (cards or stickers). Then those cards would become the physical instrument to work on their contents, find the correlations and identify the significant groups of sense.
The result is a sort of verbal and visual representation describing the first exploration of design solutions.