Advantage and Disadvantage
Rolling with ADVANTAGE is the easiest tool a Game Master has to add drama and challenge. Use it when checking for saving throws, ability checks and attack rolls when an adventurer has done something to increase their odds of success! You get to decide when and where to use it.
Advantage
A roll with advantage is as simple as rolling two twenty-sided dice for a single check and using the higher number.
Disadvantage
A roll with disadvantage is as simple as rolling two twenty-sided dice for a single check and using the lower number.
For instance, use ADVANTAGE when an adventurer needs to make a climbing check and uses a rope or climbing tools. Use disadvantage on a Perception check if the hero is stuck in a thick cloud of fog.