One should not add salt to dry beans while cooking as it hardens the
shell and makes them tough. If you need to add salt do it after they
are completely cooked.
Beans are a problem and it took me quite a while to learn to cook
beans. For one thing, soak them over night; but always rinse and
the water before cooking them the next day. During cooking, never
water. If you must add liquid, warm it first.