Advantage

Certain situations in the game will put your character at either an advantage or a disadvantage.

If you are at an advantage, you will roll your d20 twice, using the larger of the two numbers.

If you are at a disadvantage, you will also roll your d20 twice, but you will use the smaller of the two numbers.

Your GM can tell you when to roll for advantage and disadvantage, though certain item and skill descriptions will also inform you of when to roll.