Beans take a long time and heat to become tender. They also require a lot of water. This is because they are very rich in starch. So, I recommend soaking them at least 12 hours in advance to swell them with water. Think of this as passive cooking. In addition, it makes them more edible and digestible. Add a good pinch of salt and baking soda, which will result in a more alkaline pH, and thus more tender beans when cooking.