Rule 603.1 · Handling Triggered Abilities
Triggered abilities have a trigger condition and an effect. They are written as “[When/Whenever/At] [trigger condition or event], [effect]. [Instructions (if any).]”
Subrules
A triggered ability may include instructions after its effects that limit what the ability may target or state that it can’t be countered. This text is not part of the ability’s effect. It functions while the ability is on the stack.
A triggered ability may have more than one trigger condition, and an instruction that refers to whether “all” of those conditions have happened during a particular period. This refers to whether or not all of those conditions have occurred during that period, regardless of whether that ability has triggered based on those conditions.