The concept is the idea to be brainstormed
Examples:
Brainstorm the concept, snow
Compare "snow" to a tool, a bird, a plant, a tree, a fire, a dream. Choose one beforehand.
A plant
rose, apple tree, cactus, weed, algae, daffodil
Choose from the above
A rose
Create metaphors
Create two seemingly dissimilar ideas
Choose a compressed conflict
Create more metaphors