Citation :
603.3. Once an ability has triggered, its controller puts it on the stack as an object that's not a card the next time a player would receive priority.
116.2a Triggered abilities can trigger at any time, including while a spell is being cast, an ability is being activated, or a spell or ability is resolving. (See rule 603, "Handling Triggered Abilities.") However, nothing actually happens at the time an ability triggers. Each time a player would receive priority, each ability that has triggered but hasn't yet been put on the stack is put on the stack. See rule 116.5.
116.2d State-based actions happen automatically when certain conditions are met. See rule 704. They're dealt with before a player would receive priority. See rule 116.5.
116.3a The active player receives priority at the beginning of most steps and phases, after any turn-based actions (such as drawing a card during the draw step; see rule 703) have been dealt with and abilities that trigger at the beginning of that phase or step have been put on the stack. No player receives priority during the untap step. Players usually don't get priority during the cleanup step (see rule 514.3).
116.5. Each time a player would get priority, the game first performs all applicable state-based actions as a single event (see rule 704, "State-Based Actions"), then repeats this process until no state-based actions are performed. Then triggered abilities are put on the stack (see rule 603, "Handling Triggered Abilities"). These steps repeat in order until no further state-based actions are performed and no abilities trigger. Then the player who would have received priority does so.
