Use a weight to make sure that the beans remain below the brine. Cap with a lid that will let CO2 escape as the ferment bubbles. (We just got a lil kit, but you can make your own a lot of different ways)
Place the jar somewhere dark (a kitchen cupboard is perfect) to ferment for 2-3 days. We might try to ferment for longer and see how it goes. But after 3 days the beans will be fermented but still crisp. Store in the refrigerator and eat within 1 month.
Fermentation can be used for long-term preservation but I think this recipe is not quite fine tuned for that. However, if you go to the link above, the author has guides and stuff for making that happen!