If you'd like to use dried chickpeas, use about 3/4 heaped cup (6-7 oz). (Here's a great, detailed guide on cooking chickpeas from the lovely Ali at Alexandra Cooks.) First, soak them in water overnight (Ali also adds salt). Bring the drained chickpeas, 4 cups of water, 1/2 tsp salt, and 1 tsp baking soda to a boil. Then lower the heat and cook for around 45 minutes, until soft. Discard any scum that rises to the surface.