Encounter Mode
Encounter mode is used for combat and other time-critical situations. Time is measured in rounds (approximately 6 seconds each).
Starting an Encounter
The GM calls for initiative when combat or a time-sensitive situation begins. Each participant rolls initiative (usually Perception, but some exploration activities allow different skills).
Your Turn
On your turn you get 3 actions and 1 free action. You can use actions in any order. Common actions: Stride, Strike, Raise a Shield, Cast a Spell, Interact.
Reactions
You get 1 reaction per round. It resets at the start of your turn.
Ending an Encounter
Encounters end when one side is defeated, surrenders, flees, or the situation is resolved. The GM determines when to transition back to exploration mode.
No Surprise Rounds
PF2e has no surprise rounds. If creatures were undetected, they may be hidden or undetected when initiative starts, but everyone rolls initiative and acts in order.