Let’s say you have 1 in a certain stat, and you get a negative modification for some reason. You can’t roll zero dice, so instead, you roll two dice and read the lowest result. For instance, if you rolled a 2 and a 4, your result is 2.
In the full game, there will be different kin to choose from—and some of them have certain stat bonuses and penalties. And under particularly favorable or unfavorable situations, you might get a modification to your roll.