Store them in a cool, dry place away from direct sunlight. Fresh, raw yelakkis are green. They turn into golden yellow on ripening. Look for brown speckles and yellow skin to identify ripened ones. 
Slice them onto pancakes, blend into smoothies or add to fruit salads. Heat brings out the bananas creamy sweetness. Try baking or sauteing them with butter and sugar for a delicious dessert. 