Hiding

Core Rules v2 p. 8

To hide in combat, you must have Cover from the creatures you are attempting to hide from and use an action to make a DC 10 Stealth check (if you have Full Cover, you succeed automatically). The first attack you make while hidden is made with advantage, then you are no longer hidden. Most creatures will not prioritize hunting for hidden heroes while other dangers remain.

Related Rules

3
ConditionsReference / Indexes
CoverCombat / Positioning & Control
SkillsFundamentals / Stats, Skills & Checks