You can eat undercooked beans and they will not harm you.
Although undercooked beans will usually be harder to chew and swallow and digest as well.
I prefer to have my beans fully cooked or I cannot eat them because they are hard to chew and swallow.
Beans are enjoyed best when they are fully cooked and if you add some bacon, and some bean seasoning to the beans they are much better tasting.
To cook beans on the stove just use a cooking pot and fill the pot about half way with beans.
Then add water to cover the beans.
Next bring the water up to a boil and then turn it down to simmer so that the water does not boil over.
Cover the pot with a lid but leave it open slightly to allow steam to escape and check the beans every 10 to 20 minutes and stir them.
Add more water to the beans when needed.
It can take around 8 hours to fully cook beans on the stove depending on how many beans you're cooking.
Some beans may cook in as little as 3 to 4 hours to always make sure to check on the beans.
When the beans become soft then they are ready to serve or eat.