can you explain priority, holding priority, and how it works in a multiplayer game?
APNAP stands for Active Player, Non-Active Player, and is the order in which almost anything in the game is done if more than one player needs to do it. First the active player (the player whose turn it is) will make his or her decision or perform some action, then each other player in turn order will do the same. The active player is always the first player to receive priority in a given step or phase.
Priority is the system whereby players are allowed to cast spells, activate abilities, and take special actions. Only a player with priority can cast a spell, activate an ability, or take a special action. (With the exception of generating mana via mana abilities when a mana payment is required by that player.)
The Stack is a zone like the battlefield or exile. It’s where we put spells and abilities that are waiting to resolve. Spells and abilities on the stack resolve in a last in, first out (LIFO) order. This means that the newest object on the stack will always be the first to resolve.
Any time a player would receive priority, we first check state-based actions and deal with those, then we put any triggers that have triggered onto the stack. If multiple players have triggers to put on the stack, they’re put on in APNAP order. Once there are no more state-based actions to deal with or triggers to stack, the player finally receives priority.
When a player casts a spell or activates an ability, that player will receive priority again afterwards.
When a player passes priority, the game checks state-based actions and triggers again before priority passes to the next player in turn order. A player must announce any mana in his or her mana pool when her or she passes priority.
When all players pass in succession, the top object on the stack resolves, or the current step or phase ends if the stack was empty.
Players can always add new spells or abilities to the stack if they have priority. At no point do we “resolve the stack” without players being able to respond.
Holding priority just means that you want to respond to your own spell or activated ability.
Holding priority doesn’t stop your opponent from being able to respond afterward, though. They’ll still get a chance to respond before the spell or ability resolves.