Pour your beans into a bowl (no more than 1/2 full).  Add your baking soda (or ACV) on top.

Fill your bowl with water to cover the beans by at least 1". The beans will absorb a lot, so check them after a few hours and add more water if needed.

Let your beans sit for about 18 hours. Longer is good, too, but drain the water, rinse the beans, and add new water if you let them sit for a long time.

Once they're soaked, drain them and rinse them.

Add them to a large pot and cover them with fresh (filtered) water by at least 1".  Turn your pot on medium-high and simmer for 1 - 2 hours, until beans are soft.  Salt in the last 10 minutes of cooking.  (They don't soften very well if you add salt initially.)